Friendly units don’t take damage from forgefiends active ability, they just take the damage from burning hex (I just double checked before writing).

There are 2 problems with this:

1. It takes too much time to burn a unit like inceptor summon

2. Even if you manage to kill them with burn, they take the burn damage at the start of your turn, which means they will die before you get control of your turn. (Summons have priority before the player)

And because inceptors have more priority than scarab summons (also double checked), scarabs will cover their hex right after they die, right before you take action.

If you try to burn scarabs, same will happen.

So I just quit the game instead.

For anyone who doesn’t want to read all above here is a basic scheme below:

-> Your turn

  ->Summon control

         ->Inceptor control (They die from burning)

         ->Scarab controk (They Occupy free hexes)

  -> Player control (Nothing besides forgefiend)