what exactly does this thing do?
it says in the description that it can heal th owner but theres no option to, it told me to kill kill kill in baator but when i got out of baator it apologised for its behaviour, it also says im vaguley familiar, what exactly is this thing useful for? its not a brilliant weapon so what are its uses?

To gain it's healing effect just keep it equipped (regeneration rate faster).
Why is it apologizing? Try to equip it in Baator and you'll see