Remilia lived in Halloween Town before she moved to Gensokyo:
So now we've got Flandre x Marx, Sakuya x Dio, Meiling x Krizalid and now Remilia x Jack? Now we only need someone for Patchouli and Koakuma. Although, if Koakuma is indeed an succubus, she'd do it with anyone, regardless of gender. If that is the case, I expect Koakuma x Etna.