>>10067693>>e becomes Sairei no Hebi in the battle against Sabrac, right? So, that may be in 3-5 chapters from know, no?
He becomes Sairei no Hebi Sakai Yuuji at the end of next week, if not in next week's episode.
Next week will be Shana and Kazumi's "big kick off" where they force Yuuji to pick between them. As he's brooding over it, Hebi appears and talks to him, they merge, he becomes a Tomogara, disappears totally and rooms in Sereiden.