Devil May Cry - Threesome One-Shot: Dante x Oc x Vergil

Alexis Vanguard is a half-demon who’s also a demon hunter. She’s a childhood friend of the Sparda Twins. Once she grows up, she became a demon hunter and partner up with Lady. At first, Lady tries to kill her, but finally comes to an agreement with her. And now, they work together, but Alexis still gets on Lady’s nerve from time to time only because she loves her, or so Alexis claim. Alexis also lives with Dante.

This is also inspired from the Manga You're my loveprize in Viewfinder in vol.35