VanVen

VanVen is a Slash ship between Ventus and Vanitas in the Kingdom Hearts series.

Canon
Vanitas was created when Master Xehanort extracted the darkness from Ventus' heart. He was born as a faceless being with red eyes. However, a dying Ventus was eventually saved by a newborn Sora's heart. Vanitas was affected by this and was transformed into a form similar to a teen-aged Sora. He was initially sad upon being separated from Ven and wondered about the purpose of his existence. Vanitas felt that he could not stop himself from hurting Ven if he remains nearby so Master Xehanort took him to live with Master Eraqus. However, he greatly started to miss him after they were separated and learns that forming the X-blade is the only way to end this pain.

Four years later, Vanitas appeared to Ventus in his room while wearing a mask. He saw Ven as a loser and wanted to shape him up. Vanitas warned him about his best friend Terra falling to the darkness so that he would be motivated to leave the Land of Departure. It worked and Ven left the world in order to chase after Terra. During the course of Ven's journey, they encountered each other a couple of times. They dueled at one point and after Ventus learned about the X-blade, Vanitas threatened to kill Terra and Aqua if he refused to fight him.

Ventus arrived to the Keyblade Graveyard for their final battle along with Terra and Aqua. Ven was frozen by Master Xehanort at one point and was left helpless on the ground as Vanitas attacked Aqua and left her unconscious. He threatened to kill her which caused Ven to free himself from the ice through his own will. Afterwards, they fought and Vanitas revealed that he was the source of the unversed. They were soon forced to fight for one final time inside of Ven's Station of Awakening. Vanitas instructed him to fuse with him but Ven decided to destroy him instead. Vanitas warned him that it would hurt him too but Ven did not care and managed to defeat him.

Fanon
VanVen is a rather popular Kingdom Hearts ship. Even though the two were enemies and ended up fighting each other multiple times, many fans feel that the two would still be great together. This especially became the case after more on the background of Vanitas was revealed and it was shown that he was always curious about Ven and was sad to be away from him. Ventus and Vanitas are literally two halves representing light and dark so a lot of fans feel that they balance each other.

Trivia

 * Vanitas looked like a monster when he was first created but took on an appearance similar to Sora when the latter connected to Ventus.
 * The name Vanitas was chosen for multiple reasons but one factor was its similar sound to Ven's name.