If Ven is in KH3, he should narrate some of the cutscenes (sometimes flashbacks) about what was going on right not or in the past.
If Roxas is playable for time traveling, he may recieve visions from the past while Ven talks to him. Below for example.
- Before going to the past- Ven explains tells his story about his battle in the Keyblade Graveyard and the outcome of it. After his battle with Vanitas, his heart has made its way all the way to a young boy with brown spiky hair.
In the present, Ven narrates about what has been happening in Sora's quest (mostly after bosses important to the storyline).
Now what do you think about Ven narrating?