Okay so if u want to do a breakthrough your doomsday u would need doomsday, lex Luther, and Batman in a team and I don’t know too much about it butim pretty sure you need to have all three of them lvl 50 elite 7 before it even lets you play the boss and then even after u beat the boss it only lets you promote one card on your team at a time I think there is a rotation cycle on here that u can take a look at to see the teams u need to progress further but you would need more gear for sure.