Well then, since the others are here I may as well spill the beans~~

He’s sad because the fandom keeps forgetting about his existence.

We asked this question on the chapter poll and so far 82% believe that Mr. Xaver is the previous Beast Titan. It’s a popular idea. One of the most popular I’ve seen. 

I’m not opposed to it, but I’m not convinced. I’m far more interested in Zeke’s emotional tie to the man and how that relates to his mission. It could be that Mr. Xaver was simply a kind, sincere man, someone special to Zeke, who was tragically killed as a result of Marleyan cruelty. Conversely, Mr. Xaver could be someone Zeke befriended and trusted who was later revealed to be manipulating Zeke.  Either scenario could be the reason for Zeke’s total aversion to relationships and emotional ties with people.