Totally not inspired by a certain cockney-accented Overwatch character.
A guy who has the power to reset people and objects to a point where they were previously. I'm thinking the time he's allowed to reset varies on the object...
For example, he gets shot... so he rewinds his personal time back 5 seconds to a point in time where there isn't a bullet in his gut. Another example... his soda has gone warm and flat, so he rewinds its personal timeline back a few hours to when it was fresh and had a couple of non-melted icecubes in it.
This... could make him super powerful. It gives him an indirect form of healing factor... plus he can heal other people. Depending on how far back he can reboot objects, this theoretically means he could deconstruct things to their component parts, if we're talking about months or years of rebooting.
The weakness could be time, as mentioned above. His limit with himself and other people might only be a few seconds. It would also require physical contact and could be quite exhausting for him. He could save himself from a bullet, sure... but it'd still leave him quite fatigued if he had to do it repeatedly. Same with rebooting a lot of objects or a very big object.
Oh, let's not forget the practical applications! He will be able to have as many orgasms as he wants.
Refractory period? Nah! Just reboot back to a time where he can stop himself. His partner just had a mind-blowing orgasm... send 'em right back into it!
Personality wise? I'm not sure yet. I think there's a real clock motif to be had, with circular thinking being a major facet of his personality. He's always going back, rebooting both with his powers and in his mind.