Posts from How to make a hero neutral. Auto-translated

How do you make a hero neutral, not tied to a player, like a final boss?

On the map, it won't work; the hero will simply disappear (the hero must have a player assigned to it). Perhaps you could launch a battle with a neutral hero using a script; I saw a map with this feature on a forum somewhere.

Using the script command SetObjectOwner, where the new owner is a player who is not on the map.

Added 30 seconds later
This is not possible if there are 8 players.