[quote=chukklehed]
Justin law is a death scythe, and I don't know who the other one is.
[/quote]

[url=http://souleater.wikia.com/wiki/Giriko]Giriko[/url]? He's the Demon Chainsaw, autonomous, loyal to Arachne... Ringing any bells?

EDIT: Also, Jivusa, a sword is a very easily wieldable Weapon, and there's nothing stopping him from gaining a Meister... Justin Law, on the other hand, is a Guillotine (which only someone like Shinigami could wield) and Giriko's chainsaw form is so huge he had to build himself a 20 foot tall golem to act as a Meister, and even then it wasn't particularly effective. He was always more dangerous on his own, because of his chain.