It's the ability to "heal negative status" they get when you have a high enugh social link. After they hit an enemy's weakness, they MAY help another character to recover from his/hers bad status.
persianpup said: He does use wrenches as weapons at first.
No, he starts with knives, but any sane player would get him the Skill Spanners (the weapon I think he's holding) as soon as they can. Hint for anyone who doesn't already know: they're in Saki-senpai's shop, after you beat shadow Yousuke I believe.
