Who should I choose to fight against Conflux?

I agree, two months is too long. It's strange why he didn't choose Haven! If you're on a team with a friend, take Necropolis, and let him take Inferno. Choose Tanta, and within a week, build skeletons, clothiers, zombies, a Citadel, a Converter, and, if possible, a Castle. Let Inferno send you resources, artifacts, gold, and meat for the skeletons; set up a chain of heroes. On the eighth day, pass the chain's growth to Tanta and attack first with clothiers (7 stacks of one unit each) until you run out of mana, if possible, attack them all. Aislin often drops for Necropolis; they are ideal for controlling clothiers, and Meteor will reduce the fairies. Then attack with Tanta, and it's the end for Grindan the Small. Without mana, this mage will have a hard time. The main thing is to work together. Remember: Inferno is the supplier of meat and gold, and Necropolis is the striking force. Good luck.