Inferno tactics.

1. Use diplomacy =) A bunch of upgraded vampires and a cloud of skeletons can't compare to an army of archangels and various dragons. And the one who finds and levels up a diplomat faster and gathers money for an army will win. Or you can make peace (like Dirty and Forrest, if I'm not mistaken).

Diplomacy certainly makes the task easier. Demonology becomes much more profitable. But again, Galtran (or Izra if there are no rules) with hordes of skeletons will start annexing strong troops earlier. But with diplomacy, the game boils down to who levels up diplomacy faster and starts connecting. In this case, the starting castle doesn't matter much...