Board Thread:Questions and Answers/@comment-9826910-20130618064245/@comment-9826910-20130620195420

So you think he might have merged with them? By resolving the two different parts of himself and bidding them farewell to fight alone while also claiming to be Zangetsu, he may have merged with them. Like, he doesn't need to ask for their help or needs them to get out of his way or fight with him, because they've become one with him.

But why have no other Shinigami done something similar with their own Zanpakutou? Do the others value the separation between themselves and their Zanpakutou that much?