Stuck on a Steven Universe Fan Fic Plot Thread

Greetings one and all gem heads or what ever the official term is for us Steven Universe fans (I personally don't care but hey we got to be called something.) I'm looking for a little clarity on a plot line on a Steven Universe story I'm trying to write. The plot goes something like this:

Jet Black, seen here:



Is wandering the Earth, tormented by nightmare's and memories of his past as a Gem assassin (Think the T-1000 if he actually grew a conscience and was thrown in a blender with the Winter Soldier and Wolverine). Wanting to start his life over now that he's been restored (long story short he was once missing a piece of his gem and spent the last 14 years looking for it until he encounters Steven who helps him find it and heal him), he seeks to cleanse himself of the murders he's committed over the 5,300 years he's spent on Earth, but as he's starting his life over, a Gem from his long past is coming back to once more use him as a cold, unfeeling weapon.

Now, I'm not sure how to begin his redemption quest, not entirely anyway. I do have one idea where he helps out the downtrodden and homeless, but I'm open to some sort of suggestion.