I'm not so sure if I can be right but I agree with:
Nukara Rikova
Since as we all know, Ven is a character that cares a lot about his friends, Imagine you sudenly discover that, I can imagine that even maybe via Sora, why you may ask, well the one who opens the door of Kingdom Heart will be reborn, what about that ... well was on a Xehanort report but it says that will be beyond any human, whatever it also come with it, I guess maybe Sora will get some kind of revelation of those times, since I feel he is also par of some plan of MoM maybe, but well, whatever way or form he get to know the truth, he will want to know more, mybe seek his pass he can't remeber, I can feel he may want to know first by his own, I can even picture him feel frustrate and capable of turn down help from Terra and Aqua, even is the two of them are both his best friends, Ven will like to try by himself first is someway, I don't know you guys but if all come that sudenly, would you like to involve more people to an ancient incident that may have a lot of touchy story on it all at first? even if Ven is our Sunshine child of light, he may want to do this by himself, that how I feel, maybe with some fail attemps or some little time he would accept the help from his close friends and all but, I do think It will be a sad and bittersweet mess all that.