If it's 1v1, there's no contest against the best tank in the Frontier. @logen9f/jolius-blast-the-best-tank

I'd pick Barthalamas as my archon and a max level Jolius Blast for the unit. Jolius has Void that can defend against magic attacks. Against melee attackers, he's got Retaliate to counter attack. Then, he can raise his power and speed with Enrage when he gets damaged. The speed boost will work together with the Archon's buff and speed and will increase his chances to dodge physical attacks. The only cards that can attack him with no drawbacks are range attackers with Close Range. I don't think Ratbound Corsair is a match for Jolius Blast on a 1v1 fight.