Is It Wrong to Try to Pick Up Girls in a Dungeon? On the Side: Sword Oratoria, Vol. 4 (light novel) — Fujino Omori

Aiz finally gets a chance to meet with Bell Cranell. The Sword Princess was hoping to make amends, but she somehow comes away with a secret apprentice...

With Loki Familia's expedition fast approaching, Aiz has little time to teach Bell the basics of fighting--or to sate her own curiosity about the rabbit-like boy. But a jealous Lefiya might have more than a little something to say about Aiz and Bell's hidden rendezvous. And when Freya gets involved, there's no telling where things might end up!