Saw some of the raw. Pretty interesting.
Spoiler for 394:
I have to wait for the trans of the chapter, but what I saw was pretty much a flashback dealing with Apachi and the YAMI master. We get to see Apachi as a young child and he was lanky looking.
What suprises me was that the YAMI master pretty much looked the same as he does currently. In all honestly, I can not wait for the trans to see if the guy as Apachi's master or not. Also, Kenichi and Tirwat need to get the hell out of that room. From the looks of it, the two masters are pretty much doing their version of a demolotion team extremely well.