As several people guessed, the character bodyswapped with Schrödinger is from Doc’s Story, a short hentai manga by Hirano in which a proto-Doc character summons a catgirl demon for Hitler. (Caution: this is Hirano hentai, which means the plot is only an excuse to draw a very drippy sex scene. Read at your own risk.)

Millennium HQ.

Rip: I’m not telling you again, Schrö! Turn it down!

Schrödinger: Or what?

Rip: Or I’ll come over there and make you!

Schrödinger: I can hit a girl now, you know!

Rip: Nothing ever stopped you before!