We have just shy of a week to go, so time to start speculating about his freshly-revealed ailurophobia (one of only two potentially exploitable weaknesses we can thus far attribute to Dento, the other being his neurotic fixation with shiny tableware). What is it about the purple, upright-walking kitty cat that so rubs Dento the wrong way? What's the history behind that? Me, I think that he once perversely but unwisely tried to stuff one down his trousers, and suffered the predictable consequences. Now, just the sight of a Choroneko is enough to make him wince.
The Choroneko killed his parents by accident. That's why he and his brothers left Team Plasma.
Or...his parents are Choroneko!
He was dared by his brothers when he was a youngin' to try to give one a bath so that it would become as sparkly as him...Traumatic experience that was...
Since they clearly have no intention of telling us (for the time being, at least) I'm going with my trouser explanation. Seeing Dil brought back a lot of painful memories for him.
They gave us Hikari's "Pikari" explanation after a while. I expect them to spill the beans about Den't cat curse.