The Observer uses monster group battle commands to spawn all monsters in battle scene with some style.
Looks like battle interpreter is not supporting this yet, but battles are still playable with invisible monsters.
Battle: Instead of Alive test for Exists (not dead or hidden). Preven…
…ts that Hidden (unspawned) enemies can be attacked. Also update visibility. Fixes #330.
In Observer it works. AE has a different interpreter problem. Opening a new issue to track this.