Board Thread:Questions and Answers/@comment-37099021-20181113180659/@comment-32952945-20181113212426

I'd say Shikama Doji he is pretty much immortal and can possess multiple hosts the Hiragi's for generations as an example. He can also enter other host demon minds/heart as shown in the latest chapter when he entered Asuramaru mind which is pretty much impossible. He is also pretty powerful as they keep calling him a 'monster' or unbeliveable powerful monster by Mahiru, which is proven upon his encounter with Kureto when he commanded Abaddon to stop attacking also after he possessed Kureto you can see his strength he can augment using Raimeiki.

But if you mean a character this is my conjunction probably Saito since he modified his own body and the ability to use chains making up cutting him is impossible thus it's pretty hard harming him.