Why didn't Kenpachi Zaraki's soul killer have a name in his death?

You need to talk to the spirit-chopping knife to know its name. Although Kenba also talked with Ling Dao, it didn't succeed. Because he is single-minded, it is difficult to communicate with the knife. Personally, I think his chopping spirit should be called eight thousand streams. Because when he named the child he picked up, he always had a name in his heart, that is, eight thousand streams.