I think you need at least a full deck of unupgraded life or fire cards to be able to fully compete for those teams.
Your name and dedication are well known on this forum so I think people would love to take you on their teams. You do need a semi-full deck of cards of the element you wish to join however. Same goes for rares like Fahrenheit, Druidic Staffs and also important cards like photons, flying weapons, sanctuaries, etcetc.
You do need cards ^^