I am pretty sure he did this right. Page 22 of the rules states" If an ability would affect a concealed monster, reveal the concealed monster, then if the card was a monster resolve the effect on the monster instead.
The Outsider's text below the image is only active when it's in a lane and says monsters (which includes itself) can't gain damage during the alliance phase. Monsters can take damage during all other phases though. I think all damage done from the point it came out was during the fight phase? Note that something like Guerilla could still be done during the alliance phase as removing health is not the same as dealing damage even if the end result is the same.
@@PickleTheHutt wow, that can get complicated very easily does that means that if an enemy get health(+) "removed" , then it means it hasn't been damaged yet, so the barrier is still up even thought it has a token of negative health on it? That could be difficult to keep track of
Thank you for the playthrough, super informative and gave me a great idea of the flow of the game! Looking forward to actually reading through the rules then playing my first game!