Kuroda is always in the sauna. He is the boss of Dobu and Yano, and the childhood friend of the missing high school girl's father.
Kuroda mentioned that it was allegedly his fault that the missing high school girl from Nerima ran away from home. This is what Donraku Shofutei, an old classmate and father of the girl, told him. In episode 11 it was revealed that Donraku had been lied to by Yamamoto to withdraw the missing person report.
Kuroda is the unknown benefactor behind the foundation that supports children who became orphans after traffic accidents. Once the children don't need their support anymore, they receive a protection duck charm. These include Odokawa, and Kenshiro.
Kuroda is about to retire from his benefactor organisation as both his underlings Dobu and Yano had been arrested, and as their boss he felt responsible for the death of Yuki Mitsuya. He also revealed the one rule he enforced was "Do not kill." However, he accepted the lottery money Odokawa offered him as repay for taking care of him when he was young to keep supporting his current beneficiaries.
