Quote Originally Posted by MagiusNecros View Post
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"Eventually, I decided there should be an additional avatar/minion fighting for the player and its appearance will change as the special meter fills up."

Everything is subject to change, obviously, but Yoshi-p explicitly states this in the interview. You're right in that the Avatar seems to be functionally just a set of oGCDs, much like Edge/Flood of Shadow are presently on DRK.

How will your Avatar change as your meter fills? Well, he also states:

"When someone suggested a Chūnibyō-ish idea: a job where its power gets increasingly more intense as the battle goes on - the idea was immediately agreed by the whole team."

I suspect that the Avatar will become progressively more menacing and edgier as you build meter, until it takes over you and possesses you.