well there are more pieces to that head, it is surrounded with walls, and head is chained to them, I imagined that crown thing on its head is one point of connection, and cylinder in the mouth is the other one, also it shuts it up from talking, that thing is evil and not quite dead yet.

I’m not 100% sure what OP meant it to be, but traditionally it’s a pretty common image in Japanese folklore. Usually the cylinder is a scroll. From what I’ve read, it symbolizes that the warrior is in total control of their body and emotions.