so by now everyone knows the returned-to-origin eyes: the sort of winged emblem that forms around the pupils of demons who give in to their evil cycles/wicked phases/insert your preferred translation choice here. we've seen them on atori during the heartbreaker,
on kiriwo during the deviculum (and possibly other instances, this is just the one I remember clearly enough to go straight to it),
and, interestingly, on gyari during the idol games.
however there's also another style of eyes we see occasionally, and given the shape it may just be a pre-RTO thing (takes the < > that constitutes the main wing shape) but given the contexts we see it happen in, so far it seems more like a giving-into-the-thrill-of-desire thing than a giving-into-an-evil-cycle thing. we've seen it just recently on silvia during the meeting with zeze's brother, when his talk about creating gets her fired up,
on sabro during his evil cycle-influenced fight with atori, as he starts to find real joy in the act of savagely inflicting pain,
and, my favorite example, on opera during the second-year re-summoning fiasco, when it becomes apparent that kalego is going to make it as much of a challenge as possible.
it does seem most likely that it's a on-the-very-cusp-of-RTO type thing, but I dunno. the fact that gyari has complete RTO eyes just for a moment but seems to be back to normal later and sabro has partial RTO eyes despite being in an actual evil cycle make it kinda hard to tell exactly what's going on. also the implication that tormenting kalego is so much fun that opera would literally return to origins for it is just hilarious to me