Referencing the stage.
DT is a rather old Lucky Glauber edit I got back in April 2008 or so. Well, it's broken. He's way too fast. He lacks startup/cooldown a lot. Damage is high. His dodge is pro (he can spam it to avoid multiple hit attacks, similar to the stuff Darkflare shows). He seems scaled up. Max Mode (yellow mode) seems broken (I dunno what the blue and red modes do). Really, it looks like something that had potential, but then just lost it all somewhere.
I found this Koishi by accident on NicoNico, and well, it's not bad. Sprites are rather good. Projectiles are ungrazeable though. Her melee ability is not very good, as it's slow and range is quite limited. She has priorities on basics too. From what I can tell, only two supers, QCFx2+B, a level 2 field super, and QCFx2+C, a level 3 that shoots two hearts that bounce like pinballs. If the screen scrolls though, this move basically fails completely, and the hearts vanish offscreen. This super also gets pretty hard to avoid at times. Honestly, it's pretty good.
Char used: Koishi Komeiji by chiguma
Against: DT by Sweater
Stage: Carol Stage by MARK KAINE
BGM: Lotus Land Story - Bad Apple!! [Stage 3 theme] (remixed by unknown {video did not credit, listed it as from NicoNico})