Searching for an reincarnation manga ive once started

So the lead only had one arm and I think he learned to fight with sword. But everyone only liked the other cousin in the main family or something and they bullied them very hard idk if he had to do something with his missing arm anymore. And before his reincarnation he had like a fight with the cousin and idk if he won or lost but later on the cousin did capture him and killed him.
THEN he kinda reincarnated in a boys body (dont know the timeline tho) who was very weak and couldnt use magic or something. But the body had chi or something and no one knew?? Maybe mixing up 2 isekais at this point. But yeah the boy he went into was like a ghost then and they made a deal.
OMG if someone finds it that would be a miracle with this description