I forgot I wrote up these rules a while ago to use SWN for a time travel game. They seem pretty good, actually, though I'd probably decrease Fray recovery to possibly once a week instead of once a day, but I'm not sure. Also, I thought I'd give a little glossary, as the terms I present are pretty thematic.
Also, the system I present is more "hard time travel." For example, touching a past version of yourself would most likely cause the instant Unravelling of a Stitch, as well as probably yourself.
Pattern - The "correct" events of a universe's timeline. Also the term for the "rating" of a universe
Weave - The entire infinite multiverse
Ribbon - A pattern's linear timeline
Block - A group of universes based around a similar event e.g. Lincoln's assassination or 9/11
Spool - Your home point on a Pattern's Ribbon e.g. everybody's current Spool would be 21st century Earth
Needle - A time machine, usually in the form of a watch or other small device
Weaver - Someone who travels through time and space to fix paradoxes
Stitch - An individual alternate universe to an event. Multiple stitches make up a Block
Loom - The very progression of time and space, as well as the power behind it
Thread - A person's metaphysical "stability."
Unravel - The eventual destabilization of a Stitch due to paradoxes
Fray - A person's "personal Unravel"
Patterns are the alternate universes of different time lines. Every event in history has a "Regular" pattern, which was the normal turn of events. The Regular Pattern could be seen as a constant ribbon of "real time." However, when that reality was made, an infinite amount of alternate universes to the event, called Stitches, inhabited the local metaphysical area, called a Block.
Each Stitch has a rating, known as a Pattern. This determines how different it is from the historical event of the Regular Pattern. The ratings, in
escalating severity, are Light, Thin, Heavy and Dark.
A Light Pattern is almost identical to the Regular Pattern. Perhaps something small has changed, like leaves are normally blue instead of green, but the event of the Regular Pattern remains relatively the same. Light Patterns are often not to be bothered with.
A Thin Pattern is moderately different from the Regular Pattern. The event is markably different from the Regular Pattern, but usually on a small scale. For example, a famous artist may exist in the Regular Pattern, but he is a mass murderer in the Thin Pattern.
A Heavy Pattern marks a radical change from the Regular Pattern. The change is extremely blatant and often world changing. A Heavy Pattern could be one where the Aztec Empire never fell, Hitler was never born or advanced technology was discovered hundreds of years before it should.
A Dark Pattern is extremely dangerous and strange. This represents something totally alien from the Regular Pattern. Perhaps instead of humans, the main residents are sentient snails or some other odd thing.
A Stitch is any of the infinite alternate realities spawned from any point in time. Once the Stitch is created, it is realtively stable; it will
continue on in its own time stream forever, progressing history as normally as possible.
What is interesting about a Stitch is that once it is formed, it can never change: Stitches can not create Stitches. Though you can travel through time within a Stitch, Stitches can never spawn alternate histories. This applies to the Regular Pattern as well; the duel at the O.K. Corral should not be stopped.
What happens if something were to happen to a Stitch that would normally spawn another Stitch? The Stitch begins to Unravel.
Unraveling represents the Stitch coming apart at its seams at a metaphysical level. In layman's terms, this means that the Stitch begins to vanish, along with all the residents of it. The stitch unravels faster depending on how tampered it is: a simple civilian death that shouldn't have happened could only speed up the "natural" death of a Stitch by a day. However, something like introducing psionic powers to a group of stone age warriors could unravel a Stitch in a matter of days. Be sure, Unraveling is probably the greatest pain you could feel: not only physical, but mental and spiritual agony. A Weaver's main job is to travel the Weave and prevent Stitches from unraveling.
All travelers of the Weave risk much by navigating the fibers of time. As a Weaver moves farther and farther back from his own time, he becomes disassociated from his home universe, also known as his Spool. He loses what base reality he had grounded in his Spool. Weavers can never become lost, as a metaphysical "thread" can always guide them back to their Spool, but the farther they journey, the more worn and frayed the Thread becomes.
Anyone who navigates the Weave has a Fray score. Fray starts at 0, but its maximum cap is equal to the average of the character's Constitution and Wisdom scores. Fray can accumulate a few ways, with the first being travelling to a Stitch.
Whenever a Weaver travels to a Stitch, they must make a Tech save with a penalty to their roll. This penalty is equal to the amount of centuries that the Weaver travels, rounded up at 50. For example, if a group of Weavers traveled 267 years in the past, they would make a Tech save with a -3 penalty. If they only traveled 217 years, they would have a -2 penalty.
Further, a modifier is added for every Pattern Rating they Weaver navigates: 0 for Regular, -1 for a Light, -2 for Thin, -3 for Heavy and -4 for Dark.
To summarize, if a Weaver wants to travel back in time 120 years to a Thin Pattern, he has a -3 penalty to his Tech roll.
If the Weaver does not succeed on his Save, though he arrives at his destination, he gains a point of Fray. As Fray accumulates, a Weaver will become more and more paranoid about his time, possibly believing that his Spool does not exist or he does not exist.
If a character ever gains enough Fray to reach his Fray score, they Weaver's Thread "snaps." This means that the Weaver can never return to his Spool. In fact, he can not inhabit any Stitch at all; he is thrown out into the Weave, forever cursed to bounce along the interdimensional fabric, never dying and never living. It is a terrible experience.
All is not lost, however. Fray decreases with time; for every day of rest, a Weaver reduces his Fray by one. This represents him gathering his thoughts and rationalizing his journey through time and space.
In addition to granting the owner the ability to travel through time, a Needle also gives the Weaver access to the Loom.
Loom is what writes the Stitches, what carves and creates them. However, that level of power is far too great to be manifested into the Needle, no matter how powerful the device is. The Loom, however, grants a suite of abilities that a Weaver can use to alter his personal timeline, or even the timeline of others. These powers are Shedding, Picking, Battening and Unraveling. Though these powers automatically work, you must roll a Tech save or gain Fray. In fact, Battening and Unraveling are so powerful, they will inflict Fray just from use.
Shedding: Shedding is used to slow down an opponents timeline, wearing away at their very being. Any opponent in sight can be Shedded. When they are, the gain a few penalties for a round: they have -1 to all their attack and damage rolls, they add +1 to their AC, and they can only move at half their normal speed. Further, the opponent can only do a move action or a normal action this round, not both.
A Weaver can choose to increase the power of his Shedding if he takes a penalty to his Tech roll to avoid Fray. He can increase the duration of the ability for one round for every -1 applied, and he can also affect another opponent for every further -1 applied. That means a Weaver attempting to Shed three enemies for 2 rounds has a -3 modifier to his Tech save to avoid Fray.
Picking: Picking draws out the loose fibers of the Weaver's Thread or perhaps an ally, increasing the speed of their own timelines. Any ally in sight, including the Weaver, can be Picked. When they are, they gain a few bonuses for a round: they have +1 to all their attack and damage rolls, they add -1 to their AC, and they can make an additional movement or action for the round. Further, they double their movement rate.
A Weaver can choose to increase the power of his Picking if he takes a penalty to his Tech roll to avoid Fray. He can increase the duration of the ability for one round for every -1 applied, and he can also affect another ally for every further -1 applied. That means a Weaver attempting to Pick four allies for 3 rounds has a -5 modifier to his Tech save to avoid Fray.
Picking also has an alternate use: at any time, the Weaver can take any amount of Fray on an ally and apply it to himself. For example, Sarah and John both have Fray. Sarah currently has 5/13 Fray, and John has 9/11. John is dangerously close to snapping his Thread. Thus, Sarah decides to absorb some of John's Fray, in this case, two. Sarah "picks" John, causing her Fray to increase to 7/13 and causing John's Fray to decrease to 7/11.
Battening: The Weaver beats at the very fabric of time, organizing it to his liking. The Weaver freezes time for everyone except himself for 1d4 rounds. He can not be harmed from natural hazards such as fire, poison or ice, and he can easily walk across most liquids. When time returns to normal, all things that the Weaver did occur at once: that means that a Weaver could attack an enemy four times while Battened, and when time resumes, hundreds of cuts or bullet wounds would appear on the enemy.
Because of Battening's power, Weavers who use it ALWAYS gain Fray. They gain 1d4+1 Fray, though they can make a Tech save to reduce the amount of Fray by half.
Unraveling: Unraveling is the worst offense a Weaver can inflict on someone. He tears apart their very being, leaving their opponent as nothing.
The Weaver can Unravel anyone within his sight. When he Unravels the enemy, the enemy instantly dies; no saves, no nothing. An Unraveled enemy is not only killed, but erased from all existence and history; they can't be revived. Thus, Unraveling someone important could possibly cause an entire Thread to begin to unravel. Unraveling automatically gives the Weaver 5 Fray, along with an additional 1d4 Fray. The Weaver can not attempt a save to mitigate the Fray.