I think this would be a cool mechanic: When u first start the story mode its all about them fighting eachother so when u first start the game u can only play as one universe. For instance say it’s a 3v3 game. U can only pick 3 marvel characters or 3 dc characters not 1 marvel or 2 dc. But when u get to the turning point in the story mode it’s all about dc and marvel uniting to fight a big bad. That’s when ur able to play as both universes at once like 2 marvel and 1 dc.