So I’m not convinced regression chamber is overpowered at first glance. With the elemental allies available I really don’t see how this good. Let’s just think of all the hidden costs associated with this card and what it’s realistically going to do for you, then compare it to some alternatives

It’s a combo piece that does nothing on its own which raises a huge red flag. In shadow era these type of cards are often pretty gimmicky. The harder it is to pull of the combo the more value it needs to generate to be worthwhile. How much value can you expect to generate is easily quantifiable. Two extra attacks. Let’s be generous and say you get to hit twice for 5 a piece. That’s 10 damage sounds pretty good right? Well maybe not. Because it cost you 4cc and two SE. Also you need two separate elemental allies to target as it turns an elemental to an aldmor.

The end result is even if you satisfy the condition you spent 2 cards and a boat load of resources and you are left with one ally that might have just lost its abilities and is possibly now even weaker. Imagine you draw this card on turn 4 with no elemental allies on the board. Yikes. Or maybe you have a reactory that miracously managed to survive... ok then what? You can push 4 damage to the face but at this point in the game you are no where near lethal. Alternatively you could have played an ally which is just infinitely better. So what will happen is you draw this early and you sacrifice it 100 times out of
100. Late game it could help you finish out a game or something but good luck with that