Omega no Mukotori

A young gang leader, the omega Yoshiharu, is ordered by his boss into an arranged marriage with an alpha from another clan. However, his matchmaking partner, impatient with the unwilling Yoshiharu, drugged him to put him in heat. When he is rescued by his second, Makoto, Yoshiharu discovers that Makoto is the one who is his truly destined partner. Yoshiharu is relieved that his soul mate is someone he could trust, but Makoto refused to consummate the relationship...?

(Source: Kadokawa, translated)

Note: Includes one extra chapter.