Ok. I've not seen season 3 that far, but I have seen a clip where he does dark digivolve, and around 5 or so minutes before and after that. I think I've seen the first 12 or so episodes of the first 3 seasons. Not sure how much I've seen of season 5. & a fansubtitled version of the movie, or ova, whichever it is, where Dorumon appears.