Over the course of S1 of Daredevil, a Japanese business/Yakuza/something is one of the factions of the Hell's Kitchen underworld. The others all have clear roles. The Chinese bring in drugs, the Russians distribute them, Leland Owlsley handles the finances, and Fisk keeps the law off everyone. The Japanese are a faction in this scheme, but their contribution and goals aren't clearly established. This is especially confusing when in S1E9, Speak of the Devil, Fisk requests that Nobu have a member of his organization deal with Daredevil, and
Nobu himself shows up, with some super-ninja skills.
The only other activities we see them get up to is demanding a specific block in Hell's Kitchen be handed over to them, and in S1E7, Stick, where they
smuggle a child into Hell's Kitchen.
This is kinda obnoxious to me, as it seems like all the other factions play clear roles in the season-long scheme. So what role do the Japanese faction play? What are they seeking to accomplish?