It's pretty interesting that Oda introduced this character now tho. The Kaidou/Lilin alliance isn't exactly lacking powerhouses atm, so I think it's unlikely that this character was introduced to compliment that. If anything the alliance are the ones that need a bit of help, so I'm thinking he's gonna be a very controversial character that'd help balance tings out with the alliance a bit. Would be very interesting if this character wants to kill Kaidou kinda like Ace wanted to kill WB but always gets his ass handed to him lolz...and then justification for that could be that Kaidou only treated his mom as a tool to bear him (Kaidou) a child an then killed her off
so the Kid wants revenge. In which case this raid would be a prime opportunity for him to catch Kaidou with his guard down.
Also chances are that this character makes contact with the SHs or rather Luffy in particular before the main fights starts coz he seems to be away from where the banquet is taking place atm so he might be able to notice that Onigashima is under attack or maybe he simply just encounters Luffy whilst taking a night stroll or sumin
. I say Luffy coz Oda usually seperates Luffy from the group to go in his own little adventure before they converge again.