Fact is...we don't know what Vanitas's current status is.
There are in fact 3 possibilities I can think of at once:
1. Vanitas is completely destroyed, that would also mean that the shard of Ven's heart which formed his own dark heart is destroyed as well.
2. Vanitas was re-absorbed/re-integrated into Ven's heart, that would mean that Ventus has his darkness back and that Vanitas (if his sense of self and mind still exist) is now within Sora as well
...tsk, it's getting crowded, with Roxas, Xion, Ven and then also Vanitas.
3. Vanitas's dark heart was as badly injured due to the destruction of the x-blade as Ven's was (after all, Ven's manifestation inside his heart disappeared as well), so this would mean he either has found shelter somewhere else like Ven did with Sora (possible candidates would be Riku => suit similarities and Vanitas being on DI before Ven he could have set up a back-up plan or Xehanort => indicated connection between MX and Vanitas by golden eyes, similar to Braig and Isa) or his injured dark heart faded to the RoD and is now stuck there in eternal torment.
Vanitas666 said:
That's because Ven visited Soras heart in the beginning of BBS (first cutscene). The wierd thing is that Ven went to the island because he lost all his streanght and almost died after Vanitas being created
What's so weird? The issue is actually pretty simple:
1. Xehanort tears Ven's heart out of its body, extracts the darkness and cuts off a part from it,traumatizing and heavily injuring Ven. (flashback scene 4 years before BBS).
2. Vanitas is created (at this time he either has a blank face or looks like a dark Ven).
3. Vanitas starts to feed on Ven's remaining light and power, sending his already injured heart into a critical state.
4. Xehanort notices it too late, and dumps Ven on DI to allow him to "die" peacefully.
5. That night is the same night as Sora is born.
6. Sora's heart, on its way from Kingdom Hearts to its intended body which is about to be born, gets distracted by Ven's great pain and follows the bright light of Ven's heart. It's Sora that visits
Ven's heart, not the other way around. On the broken awakening platform we can clearly see the part of Ven's heart that was cut out and is now Vanitas's heart.
7. Sora offers Ven to heal his pain and allow him to survive by connecting their hearts, which forms an incredible deep bond between both boys, and the missing part of Ven's heart is filled by Sora's heart giving some of its energy.
8. This causes Vanitas to take on Sora's looks, because the "shard" of Ven's heart that is the base for his dark heart is still connected to the rest of Ven's heart from where it came.
