I found a bug (?) in the game, maybe two. I own Sunbird and leveled the card up to max. When I start the game he is on max level and after a while he resets to level 11.
I believe I misunderstood what a Firestorm does. A friend told me: " Isn’t a firestorm just an extra chance of red gem drops? "
I thought a firestorm is that what Garuda does, with the damage. But apparently not.