“Heroes of Might and Magic V: Tribes of the East”

After each hero's turn in battle, 1 mana point is restored for every 3 hero levels (rounded up). Overall, it works well. At the beginning, it's great; you don't run out of mana. You take the Archer and go forward, crushing everyone without an army. Moreover, her mana regeneration is available from the start... Like with Demons – it's the most powerful start, but then the value of this ability diminishes – and there's nowhere to use the mana anyway.