Vindicators generated in mansions do not naturally despawn unless the world is switched to peaceful difficulty.
They do not respawn after initially spawning. Rarely, vindicators can spawn in the corridors and hallways. Vindicators spawn during the generation of woodland mansions, in groups of 1–3 inside particular rooms, sometimes accompanied by an evoker. On Normal difficulty and Hard difficulty, vindicators sometimes spawn with a randomly enchanted iron axe: the chance is 0–25%, and is higher when the regional difficulty is higher.