Wabisuke

Wabisuke (Meaning "the penitent one" or "the apologizer") is a sword bent into a square curve at the top. its command is "raise your head" however "raise your head and prepare to die" has also been used as a command albeit a longer one. It is owned by Izuru Kira and has the ability to double the weight of whatever it hits regardless of whether it is living or not. This effect is also cumulative so after a couple of hits to an enemies sword the opponent would be unable to lift it and cause them to bend over as if they are apologizing.