COMSUBIN is an Italian combat force and stands for "Commando Raggruppamento Subacquei Ed Incursori Teseo Tesei." COMSUBIN's members are combat experts and are extremely skilled with traps and guns. In Colonnello's Trial of Combat, he sent a huge rock that explodes and sets up some more traps too; however, Reborn states to Tsuna that he hasn't seen anything yet, with Lal Mirch adding on that he was just playing with them, as COMSUBIN members didn't use those kinds of tricks, giving a hint as to what COMSUBIN members were capable of.
- COMSUBIN means "Commands the Grouping of Divers, Raiders and Navals."
- COMSUBIN, exists in reality as well; it is one of the Italian Special Forces and Italy's commando frogmen combat force. Before and during The World War II, it was known as The Decima Flottiglia MAS ( Decima Flottiglia Mezzi d'Assalto a.k.a. La Decima or Xª MAS )
- In Haru Haru Interview: Dangerous, session fourteen, the interview with future Lal Mirch, she mentions that in COMSUBIN, they teach how to manufacture explosives and firearms, use martial arts, survival skills, stealth techniques in invading enemy territories, how to deliver sarcasm politely, and assassination.
- COMSUBIN uniforms in Katekyō Hitman Reborn! are similar to real COMSUBIN uniforms.