Keiichirou intercepts Noël who is being chased by Shinonome Satoru all the way down to Oomori-zaka.
Tokageil Nakushark gets his name from Tokage (lizard), shark, and maybe "gale". Because of this, his speech quirk is to throw "to ka" into a bunch of his phrases.
Ogura Toshihiro provides the voice for Tokageil Nakushark, but he's also the human form and probably the suit actor since he's a suit actor by trade.
At one point, Tooma says that Tokageil's human form looks familiar. It's because Ogura was the action director for Ep #18 and 19.