[RM2K3] LIFESTEALING WEAPON

You would need the weapon to do some damage by common event.

As in, inside a common event put, if BloodSword is equipped by _____, variable set (random number), End Event Processing.

Outside the common event, you have if hero attacks a target, deal that variable in damage, deal that variable (or inside the common event store another variable which divides by 5) in healing. It's pretty clunky, but that's kinda what there is.