User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-28626666-20171226130555/@comment-2601:8C:601:5692:8493:9949:ADF9:B1B2-20180103161647

I only have info from a secondary source in the form of the Jap wiki but it seems that Kanzaki's name came up in a random discussion by the Vali Team in which they list several candidates for the "position" of "Strongest Human". Other than his name, Kanzaki's nickname (which is more accurately something like "Original Darkness") is established, as well as that he manipulates the two remaining Longinuses. While this most likely means he's their owner, it could alternately mean that he has their actually possessor(s) under his command.

The other candidate include: Arthur, Strada, Cao Cao, and Ikuse Tobio