Okay DERQ3 impressions so far. I can understand that Arata is either brainwashed or this is a copy of him since the song of the trailer is named ''Over my Dead Copy''. Similar to Mary Skelter, the trailers tend to have spoilers of some sort to the game even if not necessarily in the lyrics (MS2's lyrics are all about witches casting spells, but the spoiler is on the images displayed like the sequence of characters, the clock ticking backwards)
Regardless one thing I missed a lot in DERQ1 was that Arata had an avatar of his own but he never used it, being relegated to the Enigma avatar with admin privileges. That was better in the long run specially since Shina and the rest of the girls could fight so the admin privileges were a bigger difference. I still felt this was something that could be explored. DERQ2 is even worse because nobody's powers matter in the story as if combat doesn't exist at all. They could slay a monster that spews fire and in the next moment get overpowered by cultists.
Whether this is his avatar being used or not, it shows he is a force to be reckoned with the hacking of reality and manipulation of bugs to the point he assumes an instance similar to Ripuka in DERQ1 as an unbeatable foe laughing mad and trivializing the party opening the prologue beating the main heroines of the 3 entries as if they are nothing.