[quote=@Nemaisare]
Hmmm... I have to say that  there does not seem to be a lot that one can do with shadows,them being intangible manifestations of a lack of light, but if you can reshape them, I suppose that might have some bearing on, I dunno, freaking people out if they're around the corner. Manipulating it wouldn't really do much, that I can think of. Maybe I'm just thinking too small. But I can see useful implications for traveling through shadows if the character can then turn shadows into doorways. They could then potentially cut someone, if they're too big to fit or if the fall on the edge of the shadow but are pulled through. And there'd be other aspects to think of like what happens to them when they're going through the dark, and how they know where they're going. Actually manipulating shadow just sort of strikes me as hard and kinda pointless unless one happens to be in the circus and likes putting on shadow plays.[/quote]
With Nightshade we're looking at the shadow powers being similar to using a Portal gun. He can jump in one shadow and immediately out of the other as though they were directly connected, and wouldn't spend any time suspended 'elsewhere' between the two. Nightshade can transport anything he's in physical contact with through a shadow with him, including other people and potentially a vehicle he's riding in as long as he could concentrate hard enough to make a portal big enough. And yes, he could grab someone, pull them back halfway through and then shut off his power to slice them in half, but this would involve him actually being able to grapple the other character first in order to pull them back into the shadow.

[i]Note to self:[/i] Need to think about angles of shadows, as stepping into a shadow on the wall and then dropping from the ceiling or vice versa could be possible. Also dropping a target through a shadow on the floor beneath them would be a little too easy.

[quote=@Nemaisare]
I do have a suggestion for Slice and Tempus, though the latter would likely only work if it's a turn-based, tabletop thing. Which I'm assuming it is based on what's been said so far. But rather than letting the character go back in time as many times as he can withstand, even if it is only for a few seconds, why not allow them to mess with time without being able to go back themselves? I think it's the spacetime theory? But if they could flip the order of two actions around in one or two turns, only two actions mind, and only things within a certain timeframe, that might give them a little more leeway, without either taking away the point of time travelling(a few seconds really isn't a long time at all) or giving them too much power.[/quote]
The game we'll be playing is a tabletop turn-based system, with dice rolls to determine the success of actions and attacks, which allows for Tempus rerolling failed actions as he steps back and tries the same action in a slightly different way.

The problem with flipping actions is that if you replace something which happened in the previous round then the whole chain of events collapses, with every action past the point of change needing to be repeated. As an example, the party are in a hallway as the door ahead opens and a group of three guards arrives. One of the party shoots down the hall until they run out of bullets and kills a guard and another member of the party charges forwards to engage a second guard, slicing them down with a sword. Tempus pulls out his gun and shoots at the third guard but misses.

In the reroll model Tempus would jump back a moment and retake the shot, aiming a little to the left this time and hitting the third guard. In the flipping model Tempus jumps back to before the other party member shot and aims for the easier target who was killed by his colleague, stealing the kill for himself instead. The problem then is that the first party member's shooting attack now needs to resolves again against the two remaining guards and the second party member's charge would have to be resolved again, and so both the players would have to roll for their actions again even though they'd already succeeded. While this is better for Tempus it means you'd spend most of your playing time going back and replaying the same scenes again as each temporal incursion alters the flow of events.

[quote=@Nemaisare]This would need more thinking about, certainly, for instance, would causal actions be switchable, like throwing a glass and it breaking, or hitting someone with a sword and them falling over? And how much leeway would they have in defining a causal action if they aren't switchable?[/quote]The definition I usually use for a 'casual action' is something which has no effect on any character other than the one performing it. If they place something in their pocket or pick something up then that's casual, but if they interact with someone else, like hitting them with a sword, then it's not casual as the other character would need to have a chance to react to either prevent being hit or recover from the attack. Throwing a glass and it breaking may be casual or not, depending on the circumstances. If you're hiding and try to use the glass as a distraction it wouldn't be casual (the people hunting you would need to respond) but if you're in the middle of a friendly meal and toss the glass away then it's casual.

[quote=@Nemaisare]Someone drinking wine after it's been poisoned vs before it's been poisoned, for instance.... If that's something you wouldn't mind allowing, then you could say that the character would have to be able to guess or know which actions would achieve the goal they want(so they might not succeed in whatever they're trying to accomplish even if the actions do switch) and both actions would have to be within that limited timeframe(ie if someone had poisoned the wine days before it was drunk, they would have to find another solution, if they can).[/quote]One of the rules I'm imposing for Tempus is that he's physically travelling through time, and so any injury or effect he's suffered would persist. In the case of whether to drink a potentially poisoned drink or not, even if he travelled back after drinking the wrong cup he'd still be poisoned as he drank it and then traveled back and so as part of his own personal timeline the event did actually happen to him.

The main reason I'm using this rule is to prevent Tempus from becoming immortal with his powers. If the player steps out into a hallway filled with armed guards then he's going to get shot. The player would have to think their way around the problem rather than relying on their powers to get them through unscathed. However if Tempus stepped around a corner and spotted the guards before they shot he could use his powers to just back a second and decide not to turn the corner instead. In gameplay terms, the player would have to decide to make a saving roll and use the power before the enemy rolls to attack Tempus, rather than waiting to see if the enemies would manage to hit Tempus or not before choosing whether to jump back or not. In situations where he's already been attacked and injured he may still choose to go back to warn the party of an incoming attack, but would retain the injuries he'd suffered before travelling.

Similarly the precognitive ability I think you're describing reminds me of the Nicholas Cage film Next, where the character knew the outcome of every decision he could possibly make within the next five minutes, which let him walk through the middle of a battle between an army of terrorists and federal law enforcement officers without being injured, search an entire ship of mines without setting any off and finding the exact location of a hostage in seconds. All of these abilities would be far too powerful as part of the narrative and would involve the players having to either replay the same five minutes over and over until the perfect result was achieved, or simply jumping to the perfect result without playing through any of the failed attempts, which then makes any dice roll pointless as it could be simply wished away.

[quote=@Nemaisare]
As for Slice, I see the point of an adaptable arm, and the unfair point of having to know how to make a plasma blast. But I think the whole listing what's in the arm is a good idea. And might do with another list of potential possibilities so that the player and the character both know what the arm is basically capable of before starting, and what you'd be willing to allow or not allow. But a true weakness should be set in place concerning maybe, power limits(do the batteries need charging?) or weight(the more equipment the arm has, the heavier it will be, the more lopsided the character's balance...)
[/quote]The logic behind Slice's arm is that rather than having a different device for every use instead she has the components which lock together slightly differently to generate different effects. For instance the arm would have a phase coil, used to generate and control electromagnetic fields. This could be used to help control the flow of plasma, to create a magnetic force field, to create a railgun launch mechanism, to magnetise her arm, etc. Similarly the arm would have a plasma power core which could be used to project plasma, power a force field or electrify her arm.

However, if the player decided he wanted to try and use the arm to unlock a mechanical lock made out of non-magnetic components they wouldn't have a component which could be tailored to the task, so unless they could come up with an explanation as to how the plasma and magnetic fields could be used to unlock the door (other than blowing it off its hinges with a blast of plasma) then they wouldn't be allowed to use the arm to complete the task.

As far as power supply and weight goes, the plasma core uses up fuel as it operates but can also replenish itself over time. In terms of gameplay this works the same way as the Stress for Tempus's powers but in reverse where the power would drain as tasks are performed but then recover over time as the character rested. The weight issue is actually the reason for the interlocking components explanation of the arms operation, since it wouldn't need extra equipment to operate differently as long as the existing components could reconfigure to achieve the goal.