User blog comment:Llama919/Possible Beast Titan Identity?/@comment-2.51.85.17-20150909002541

I think he is either grisha's brother or someone really related to grisha or someone from the reiss family due to the fact that he said that "reclaiming the coordinate comes first", that means he needed the coordinate but it got stolen from him.

That could mean that he is grisha's brother or a relative of his, their titans kind of look similar, in fact, they both have the same ear shape, and according the newer chapters, grisha was found wandering outside the walls, that means that they could have been on a mission together but they split apart for some unkown reason, when shadis found grisha, grisha's clothes were dirty and looked like he was fighting something, it could be MT