In the Cage

Overview

Haru (omega) is in a relationship with Eiji (alpha), who is also his childhood friend. But Eiji, who is from elite family, already had his fiancé, and Haru always came in second. Renji (alpha), Eiji's older brother and Haru's first love, appeared in front of him. "I came to pick you up." Renji told Haru. Where will this complicated love triangle lead to...? (Source: Fusion Product, translated)

Source: AniList