Originally Posted by His Dudeness
Someone can explain me what is "Tav"? From context I understand - player character. Right? Why Tav? I can't find information about it.
Gustav is the codename of BG3, so Larian shortened it and made it the default name of your character as a nod to this codename.

Oh and also, Gustav is Swen pet dog! https://www.pcgamesn.com/divinity-original-sin-2/larian-project-gustav