I saw one ending of the Insanity Dlc where an older Vaas is sitting on the beach and talking to a tennis ball. Is this ending canon? The ending where Vaas dies is known as the “non-canon” ending. Thus making the one where he lives, canon.

Is Vaas insanity DLC canon?

As far as i know the dlc is canon.

Why is Vaas insane?

Hoyt and Citra had turned him into a psycho killer, they drove his mind insane and his sister betrayed Vaas by attempting to kill him with her knife despite his mind slowly descending into insanity due to drug abuse and a promise to become a warrior. .