Archived first design (v1, August 2026) — the current Lens site is here.
LENSSolo Roleplaying Engine

Chapter 1 — Lens

I reach for the door.

There is a mark above the latch: three pale cuts in the old wood, close together, almost hidden under the grain.

For a breath, I stop.

A sign, perhaps. A warning. A thief’s mark. A ward. The kind of small thing that has saved my life before, and made me ridiculous twice as often.

I lean closer.

No.

Scratches. Old damage. A careless blade. A nail dragged during some repair. Nothing with intention in it. I have spent too long in dark places, learning to see teeth in every hinge and prophecy in every stain.

I almost laugh.

“Enough,” I tell myself.

The corridor is empty. The air is still. Nothing moves behind the door. If I turn back for every scratch and silence, I will spend the rest of my life standing in thresholds, congratulating fear for keeping me alive.

So I put my hand on the latch.

The metal is cold.

Of course it is cold.

I open the door and step through as if it is safe.

Sam looks up at the ceiling, then down at her dice. Dammit, Kael, she mutters, and pulls the module closer. Why didn’t you trust your instincts?

That ache is where Lens begins.

Solo roleplaying is tabletop roleplaying for one person. Like Sam, you play a character, make decisions, roll dice, and discover what happens. Lens is a solo overlay: a way to take the rulebook, character sheet, dice, setting notes, maps, modules, and worldbuilding tools you already use, and play from inside one character’s limited view of the world.

It does not ask you to invent every twist. It does not make you pretend you have forgotten what you read. Instead, Lens uses dice, pressure, and written detail to keep the gap alive between what you know and what your character believes, notices, fears, misses, or refuses to trust.

That is what makes the experience genuinely yours. The dice can produce a session you could not have predicted, even from a story you already know. The spirit of discovery survives because you knew the facts, not in spite of it. The tension was never only in not knowing. It was in watching it arrive.

You do not have to write prose like the passage above. At the table, it might only be a line in your notes: scratch above latch; Kael dismisses it; trap triggers. Record as much or as little as you need. The richness is the experience, not a transcription you owe.

When Sam sits down to play, Lens sits beside the things she already uses. It does not replace them. It gives her a way to stay in the player’s seat while her character moves through the world one perception, choice, and consequence at a time. As Kael acts, pressure builds. Suspense gathers around what Sam knows, suspects, fears, or refuses to trust. Surprise emerges from the gap between the written world, the dice, and Kael’s limited point of view.

You already know this voice. Every Game Master leans across the table and says it: as you turn to go, something catches your eye; you feel the cold come off the latch; you flatten your back to the wall without deciding to. The small, almost-inconsequential thing, handed to the character in the half-second you thought the scene was over.

That is what a Lens roll is — that voice, made of dice. The Impulse is your character’s gut, narrated for you. Everything else in this book is built on that one familiar act.

Let’s find out how Sam does it.

Lens works with the games you already play

Lens is system-neutral. It works beside your rulebook, character sheet, dice, setting notes, maps, modules, solo tools, and worldbuilding material. It does not replace them. It gives those tools a character-facing layer of pressure: a way to keep play tense, personal, and uncertain while you stay in the player’s seat.

Lens sits as lightly over a rules-heavy game as a rules-light one — it never touches your system’s resolution, only the perception around it, so the crunchier your game, the more cleanly the two keep to their lanes.

Published adventures and prewritten scenarios

You do not unknow the module. You play the person inside it, while the truth moves around them.

Use Lens with lore-rich RPGs, campaign books, dungeon modules, mysteries, investigations, sandboxes, and prewritten scenarios.

You can read the adventure, prepare the situation, and still play it solo. Lens takes the authored material already on the page — locations, NPCs, clues, dangers, events, secrets, and consequences — and filters it through your character’s limited point of view. You may know what is waiting in the next room. They do not. The play comes from watching that knowledge press against their choices.

Lens keeps the spirit of discovery alive, not by pretending you have forgotten the module, but by making the gap matter.

Standalone solo and co-op RPGs

Your solo game says what happens. Lens says how the moment lands on the character — the pressure, the gut, the misread.

Some RPGs are already designed for solo, GM-less, or co-op play. Lens works alongside them.

It does not replace their procedures, oracles, moves, prompts, maps, clocks, or worldbuilding rules. Instead, it adds a layer of character pressure: what your character notices, misreads, fears, refuses, suspects, or cannot yet face.

That can help a solo game feel less like managing the whole world from above, and more like being one person inside it. It can also give you a way to look through another character’s eyes when you need a clearer sense of what an NPC wants, fears, hides, or does next.

Generative play and GM emulators

Your oracle generates the world. Lens decides what your character notices, fears, or refuses to trust about it.

Lens also works with generative play.

If you already use GM emulators, prompt decks, random tables, oracle rolls, hex crawls, dungeon generators, mapping games, or worldbuilding frameworks, Lens can sit on top of them. Those tools create material. Lens gives that material pressure, point of view, and consequence.

A random room becomes a place your character enters under strain.

A generated NPC becomes someone seen through suspicion, need, fear, attraction, guilt, or debt.

An oracle result becomes something your character must act on before they fully understand it.

Lens does not take the wheel. You still play. It gives the world ways to push back.

Most RPGs where character perspective matters

From dungeon crawls and hex crawls to mystery games, narrative-first games, horror, fantasy, science fiction, survival play, mapping games, and campaign sandboxes, Lens adapts because it is not built around one genre or rules engine.

It is built around a simpler fact:

You are playing someone who does not know everything.

If the game gives you a character who can think, feel, misread, hesitate, hope, fear, and act, Lens has something to work with.

You and your Host RPG

Solo, co-op, or GM-led — it is all just roleplaying. Played alone, you take the player’s chair and no other. There is no second role to assume and no screen to sit behind. You simply play, and Lens stands where the screen used to be.

Your game may state that a group is required, or that play must be split between a Game Master and players. Ignore this. The distinction does no work in solo play.

You have already seen what Lens is for. Kael did not know what Sam knew, and the distance between them was the game.

That distance has to be built. You build it by reading everything.

Sections marked GM only — or DM, Storyteller, Keeper, or Referee only — are yours to read. Scenario secrets, NPC motives, the trap behind the door: read all of it. Nothing here is a spoiler for you. What is hidden in group play is, in solo play, hidden only from your character.

You know. They do not.

Lens governs what your character perceives of what you know, and what they are allowed to treat as true, act on, or ignore — even with the whole picture in front of you.

This is not free. Lens heightens dramatic irony, and the same discipline that makes the door tense is the discipline that may get your character killed walking through it.

Two conventions, then: ignore the group requirement, and hold the line between what you know and what your character does. Those are the only places Lens overrides your game. Everything else — its rules, its dice, its procedures — is yours, unchanged.

Conventions of Solo Play

Agency is the ability to make meaningful choices as your character and have those choices matter in the fiction.

Lens does not restrict player agency.

Your character can want, attempt, risk, avoid, say, believe, and do anything the fiction allows. They can act on the world, change the situation, solve problems, make mistakes, force consequences, and react freely. None of that is touched.

What Lens restricts is something else, easily mistaken for agency: authorial control — the quiet habit of also deciding what the world means, what is true, how dangerous a thing really is, or how events ought to go behind the scenes.

That is the slip that breaks solo play.

Inhabiting the character and authoring the world are different jobs. Almost everyone, without noticing, gently tilts the world toward what they want, expect, fear, or think would make a better story. Lens does not take the authoring away from you. You still bring the scenario, the situation, the premise, the places, the people, the threats, and the questions.

It asks one thing: do not pre-author what your character’s actions will mean before the dice and the fiction have answered.

That is the line.

Inside it, your character can do anything. Across it, you stop playing a person in the world and start narrating the world’s verdict on yourself.

Held that way, Lens does not cost you agency. It returns it.

Choices only matter when their meaning is not already decided. Give your character’s actions real resistance, let consequence fall where it falls, and the choices become real ones again.

You already know how this feels. You watched Kael talk himself past the mark on the door while you sat on the other side of the glass, knowing. That gap is not a flaw to be smoothed away. It is the engine.

To this end, Lens has one core goal.

Core goal: keep you in the character’s chair

Solo play has a specific failure mode, and it is not that the story gets worse. It is that you do.

Every time the game makes you step out of the character to think like a writer, director, or GM — what should happen here, what would be good, what would make sense, what should this mean — you pay a switching cost. Do it often enough, fast enough, and you are running the game and playing it in the same breath.

You start second-guessing. Then doubting. Before long, you have lost confidence, and the character’s chair is cold because you keep getting up from it.

Lens is built to keep you in it. Not by taking the authoring away. You still prepare. You still bring the world. You still decide between scenes what kind of game this is. What Lens removes is the involuntary exit: the writer’s intrusion in the middle of a moment, the adjudication you had to leave the character to perform.

It gives that moment a structure, so you can resolve it from inside the character instead of stepping outside them to author it.

So everything stays at character level: what they notice, what they feel, their first honest impulse, the choice they make right now. Emergent story, prewritten scenario, or something with no name yet — the aim never changes. Lens is bent, in every rule it has, toward keeping you inside the fiction and out of the writer’s chair.

Using this book

This rulebook is written for two kinds of use.

Instruction. Work through the book in order. Each section builds on the last; follow the examples and do the exercises. This is how you learn Lens.

Engine. Once you know it, you do not read Lens — you run it. It stays beside your game for the whole session: not consulted every moment, but there whenever a moment needs it. Use the book as reference; let it answer the question in front of you.

Terms appear in bold when introduced, and again when they return in a context that matters. The glossary in the appendices defines them all. You do not need to memorise anything. You need to recognise a term when it does its work in play.

To run Lens alongside your RPG, you need little beyond your usual roleplaying kit: this book; dice — two d6 in different colours, one d10, one d12; and something to write on.

A note on the dice. The d10 and the d12 are not a pair you roll together — they are a choice you make roll by roll. Most of the time you reach for the d10; when the moment could admit the uncanny, you reach for the d12 instead, which opens results 11 and 12 for that one roll. It is a situational, in-the-moment call, the same shape as Follow or Resist — a thing can read uncanny here and ordinary again a breath later. Chapter 7 gives the toggle in full.

The two d6 are a matched pair. In the Yes/No oracle — Lens’s binary-question tool, taught in the appendix — one answers and one carries the Twist. You roll them together, so they must be tellable apart.

Playtesting found that sticky notes and index cards work better than a notebook for the kind of notes Lens generates. The print-and-play materials at riverportgames.com are optional but useful.

You also need time — and two kinds of it. Prep and play are separate activities, and Lens treats them that way deliberately. Prep is where you build the thing you will then get to play.

Finish prep first. Then play from the chair.

That separation matters. Lens works best when play is not constantly interrupted by the need to invent, repair, or complete the situation from outside the character. Prep gives the game enough shape that, once play begins, you can stay with the character and let the dice, fiction, and pressure answer the moment in front of you.

Your First Session

You have read this far. The book is in front of you; your character is taking shape in your mind; the adventure you mean to play is somewhere on your desk. The question is what to do next — and the answer is a procedure.

Six steps, in order, the first time you sit down with Lens.

1. Choose your source. Lens needs something for the character to bite on — the objective fact, the what-is. This is the world your character is going to move through. The more your source has already done, the more of Lens’s work is reading what is there rather than building it from nothing. Four common kinds:

Lens does not care which of these you choose. It cares only that something is there to read. Lens works with anything, but does not require any of it in particular.

2. Make or pick your character. Use your RPG’s normal character creation, or use a pre-generated one the adventure provides. The only thing Lens needs from a character is that they can perceive and can have a gut-feeling — anything that meets that bar is enough. The character (the next section) covers what counts and what does not.

3. Read what you have chosen. Read the adventure, the dungeon, the supplement, or whatever your source is. All of it. Including the secrets. Take notes if you want — the things that matter to your character, the pressures you can feel building, the people and places that might press. You know. They do not. This is the foundation of everything Lens does.

4. Ignite. Lens has a procedure for the moment just before play begins. It is called Ignition. You will run it once, the first time the character enters the situation. It produces the playable first moment — where the character stands, what they want, what is pushing back, and what their first action is. Ignition is taught in the next major section of this book. Work through it with your own material; the Sam-and-Kael example shows you the shape.

5. Take the first roll. Once Ignition has handed you a playable first moment, Lens fires. The book teaches the roll itself in Chapter 3. The Pressure Clock begins filling. The character meets the world through their own eyes.

6. Play. From here, the loop runs: the character acts, Lens reads, the Pressure Clock fills, Commits land, the next moment opens. You stay in the chair. The book stays beside you, consulted when a moment needs it.

A word on note-taking. Lens’s own record-keeping — the Pressure Card, with Commits and Beliefs written as they happen — is the canonical session log. You can journal alongside if you want, but you do not need a separate journaling system. The Card is the session.

A word on prior solo experience. If you have used Mythic, Ironsworn, journaling games, or any other solo apparatus, Lens runs alongside them cleanly. There is no overlap between what those tools do (generating fact, resolving oracle questions, supplying prompts) and what Lens does (reading the character’s perception of what they meet). If you have not used any of those — you do not need them. Lens is enough.

That is the procedure. Six steps, one direction. The rest of the book is what makes each step do its work.

The character

The character you play with Lens is the character you would play in a group game.

Same creation, same method. Lens does not change how a character is made.

If you want to use a character you already play in a group, agree with that group whether anything gained in solo play carries back. If you have a favourite and no group to answer to, run a multiverse: let the solo version diverge from the group version at a point of your choosing.

Otherwise, make one for solo play. You can keep several. You can use pre-generated characters. Lens does not care how many you run or where they came from.

What a character is

A character, in Lens, has two requirements:

They can perceive.

They can have a gut-feeling.

That is the whole definition.

Everything else is up to you and your game. A character might be a name and a difficulty rating. A name and a demeanour. A fully stated, fully articulated person with a decade of history.

The amount written on the sheet — or scrawled in a notebook, or held only in your head — does not matter. Two things matter: the character takes the world in, and the world lands on them as a feeling before it resolves into a fact.

That gut-feeling never tells you what is objectively true.

It tells you how the moment lands on the character: wrong, exposed, familiar, hungry, unsafe, charged, too easy. It pushes them to act before it has finished explaining itself.

That pressure — felt, not reasoned — is what Lens uses.

The character’s eyes

Lens works through a character’s perception.

There is no narrator. No overhead view. No godlike read of the world — unless that view is itself something in your setting that perceives and has a gut, in which case it is just another character.

Your view of the game stays behind your character’s eyes. Their experience is yours: subjective, internal, coloured by the voice that shapes what they notice, what they fear, what they dismiss, and how they react.

Picture it as a camera mounted inside their head — or, at the very least, on their shoulder.

This is what we are reaching for whenever we roleplay well: the character’s experience at the centre, not above it. Lens is built around that position.

Objective truth tells you what is there. It comes from your RPG, your setting, your scenario, your generative tools — they tell you what is.

Subjective truth tells you what it looks and feels like from inside the character’s skin.

Lens reads the subjective first. The objective emerges through play.

The Golden Question

Before a roll, ask:

Whose eyes am I behind — and what is objectively true?

The first half puts you back inside the character’s perception.

The second half keeps the facts clean. You may already know more than they do. You may have read the room description, the NPC motive, the trap, the clue, the secret, the whole scenario. That knowledge belongs to you.

It does not automatically belong to them.

Lens lives in that gap.

Once you know whose eyes you are behind, and what is objectively true, you are ready for the next step: why this character is here, what is at stake, and what first move brings them into play.

That is Ignition.

Ignition

The hardest part of solo play is often not the danger.

It is the blank page before the danger.

You have a character. You have a setting. You may even have a module open in front of you. But the moment before play begins can feel strangely empty. Where do they stand? What do they want right now? What is pushing back? What happens if this goes badly?

If you answer all of that from nowhere, you can feel yourself leaving the character’s chair. You are no longer playing the person in trouble. You are arranging trouble for them.

That is the slip Ignition exists to prevent.

Ignition does not decide what is true. It does not resolve danger. It does not ask you to surprise yourself by pretending you do not know what you have read.

It does something smaller, and more useful.

It takes the facts already available — the character sheet, the setting, the module, the pressure implied by the situation — and narrows them until there is a playable first moment.

Not a plot.

Not an outcome.

A place to stand.

A reason to move.

A cost if movement goes wrong.

Sam knows what the module says.

She has read the room descriptions. She has read the GM notes. She knows there is a trap behind one of the old doors in the north corridor. She knows the house is not empty in the way Kael would like it to be empty.

Kael does not know that.

That is enough.

Ignition takes the facts Sam already has and brings them down to character level. It gives Kael something to want, something in his way, something he can lose, and a first place to stand.

Ignition is how Sam gets Kael to that corridor without turning herself into his GM.

Sam ignites Kael

Sam has Kael’s sheet in front of her.

Kael is a thief, though he would not use the word if respectable people were listening. He has quick hands, a working knowledge of locks, and the tired caution of someone who has survived too many rooms by not trusting them.

His question is already set:

Fear, or good sense?

That matters.

Kael is not a fearless adventurer walking into danger because the evening needs somewhere to go. He is someone who has lived by reading small signs: a hinge too clean, a floorboard too willing, a silence that has weight to it.

Sometimes that instinct has saved him.

Sometimes it has made him ridiculous.

Sam writes nothing grand from this. She does not need a theme statement.

She needs the detail that bites.

Kael notices danger.

Kael also doubts himself for noticing it.

That is the first spark.

The Hook

The module gives Sam the place: an old safe house, abandoned after a raid, still holding whatever its last owner did not have time to carry away.

Kael gives her the reason it matters.

Someone he once trusted used that house. Someone who helped him when he was younger, hungrier, and easier to kill. Their ledger is still inside: names, payments, hiding places, favours owed. The kind of book that can save people or ruin them, depending on whose hands close around it first.

So Kael is not here for treasure.

He is here because the past has become physical. It has a cover, pages, ink, and a hiding place somewhere in this house.

The watch are coming back before dawn to strip the place properly. If they find the ledger first, Kael’s old debts become other people’s death sentences.

That is enough to put him in motion.

Not because the plot requires it.

Because Kael would go.

The Problem

The problem is not just the obstacle in Kael’s way. It is the obstacle, what it will cost him, and the ground he has to face it on — three faces of one pressure, not three separate things.

Sam looks at what the module already gives her.

The safe house is old. It was built for people who expected betrayal. Doors have been reinforced and repaired. Some rooms were used for smuggling. Some were used for hiding. One corridor in the north wing leads to a private room where the ledger may have been kept.

The module also tells Sam something Kael does not know.

One of the doors in that corridor is trapped.

Not dramatically. Not with a swinging blade or a collapsing ceiling. Something smaller. Crueller. A latch mechanism. A hidden bite. The kind of thing built for a hand that thinks it has already won.

Sam does not have to invent the danger.

The module owns it.

What Lens gives her is the pressure around it.

Kael needs the ledger before the watch return. The house is dark, damp, and too quiet. He cannot search every room carefully without losing time. He cannot rush without becoming the sort of fool he despises.

Every closed door asks the same question in a slightly different voice:

Is this caution, or fear?

That is the problem.

Not “can Kael open a door?”

Kael can open doors.

The problem is whether he can trust himself when every sign looks like a warning and every warning might be nothing.

If Kael fails, he does not merely miss a clue.

If he fails, the ledger reaches the watch.

Names become arrests. Safe rooms become graves. People who once fed him, hid him, lied for him, or looked the other way when he needed mercy will pay for the fact that he was too slow, too clever, too afraid, or not afraid enough.

That is what failure costs.

It is not abstract.

It has faces.

Sam does not need to name them all. She only needs to know they exist, and that Kael knows they exist.

Now the house has weight.

Sam puts Kael in the house.

Not outside it. Not planning the approach. Not circling the premise.

Inside.

The safe house has already swallowed the first part of the evening. Kael has crossed the yard, forced the kitchen door, found the cold stove, searched the lower rooms, and taken the stairs without lighting a lamp.

Now he is in the north corridor.

The ceiling is low. The boards are uneven. The walls hold the smell of old smoke and damp plaster. Somewhere behind him, rain ticks against a cracked pane.

Ahead, the corridor narrows toward a door with an iron latch.

There is a mark above it.

Three pale cuts in the old wood, close together, almost hidden under the grain.

Sam knows the module says the door matters.

Kael only sees the mark.

That is the stage: not the whole house, not the whole mission, but this corridor, this door, this latch, this small ugly hesitation before the hand moves.

The Opening Beat

Sam has enough.

She does not need to explain the house from above. She does not need to decide how the scene resolves. She does not need to make the mark important or unimportant by authorial force.

The facts are already on the table.

Kael is in the corridor. The ledger may be beyond the door. The watch are coming before dawn. The house has old teeth. The mark above the latch is visible.

Play can begin.

So Sam drops behind Kael’s eyes.

I reach for the door.

There is a mark above the latch: three pale cuts in the old wood, close together, almost hidden under the grain.

For a breath, I stop.

A sign, perhaps. A warning. A thief’s mark. A ward. The kind of small thing that has saved my life before, and made me ridiculous twice as often.

That is Ignition doing its job.

It has not told Sam whether Kael is safe.

It has not told her whether the mark is meaningful.

It has not asked her to decide what happens next.

It has brought Kael to the edge of a choice where the answer matters.

From here, Lens can work.

Kael can notice, dismiss, hesitate, act, resist, press on, turn back, or misread the whole thing. The module holds the hidden facts. The dice and Lens procedures will put pressure on what Kael perceives and what he does with it.

Sam is not writing the verdict.

She is playing the person who has to touch the latch.

What Ignition has solved

Before Ignition, Sam had a character, a module, and a house full of information.

That is useful.

It is not yet play.

Too much is still floating above the table. Kael could enter by any door. The ledger could matter in a dozen ways. The safe house could become a tour of rooms instead of a scene. Sam could spend the next ten minutes deciding what would be interesting.

Ignition cuts that away.

By the time Kael reaches the door, Sam knows four things.

Kael is here because the ledger can expose people he owes.

The house resists him because it was built by people who expected intrusion.

Failure matters because the cost will fall on names in that ledger, not on an abstract mission objective.

The first playable moment is here: Kael in the north corridor, before dawn, looking at three pale cuts above an old latch.

Sam has not decided whether the mark matters.

She has not decided whether Kael is right to hesitate.

She has not decided how the danger resolves.

She has only brought him to the point where the game can answer.

That is enough pressure for the first roll.

That is enough fiction for the first mistake.

And that is enough for Sam to find herself, a few minutes later, looking up at the ceiling, then down at her dice, muttering:

Dammit, Kael.

Why didn’t you trust your instincts?

From here, the rest of the book shows how Lens handles that gap: what your character notices, what they trust, what they dismiss, and what the dice make costly.

← Introduction2 · Ignition →