I was thinking about Gula being revealed as Ven's twin brother but that could lead their dynamic to feel like a repeat of Ven/Vanitas.
Twins would be more or less impossible as Gula is older than Ventus.
In Union Cross, Ven is about 10/11 while Gula is certainly in the 15/16 range.
It could thus be big bro and little bro, possibly a parallel to Lauriam and Strelitzia.
In the
present however they would be around the same age if Gula didn't age further which is pretty unlikely.
That situation is also present with Ven and Sora.
If the dynamic would be a repeat or not would entirely hinge upon how they feel and act towards each other.
Ven/Vanitas is certainly a toxic dynamic since Vanitas just can't let go and accept that a no means no while Ven does accept Vanitas as his own entity, with encouraging that in KH III itself, but doesn't exactly want to associate with him.
For Gula and Ven the dynamic could be different on the basic premise alone already as while Vanitas actively and aggressively stalks and bothers Ven, Gula is known to be a loner who doesn't put too much value into social interaction so he would probably give Ven much more space and while he might love his lil bro, he won't show it openly that much and it'll fall to Ven to be the active force and coerce Gula out of his introverted bubble.
Also doesn't Ven basically already have a twin in Roxas and even Sora?
While masks are often used to hide faces fans are already familiar with, this hasn't really been the case in KH excepts for Luxu. The hoods and hidden faces usually are just covering new faces. I don't expect it to be any different this time around.
Yea, with Roxas being around now this can become a dynamic down the line with Ven even if they are not
actual twins in a biological sense.
Roxas is his own being but parts of him were influenced and/or shaped by both Sora and Ven, so they could be counted as triplets.
It isn't even that way with Luxu.
We don't know Luxu's actual face because Xigbar/Braig is just his latest vessel.