Tactics for the Swamp (Fortress).

As Sage already mentioned, a swamp hero doesn't receive a penalty in swamps with their native units, but all guests will be penalized...
Lizards aren't much worse than orcs in terms of stats, and orcs are a level higher...
Wyverns are very good as attacking units in the early game, but their huge wood consumption makes you wonder if it's worth it...
If there's a Bron initially in the tavern, you can clear a lot even without wyverns...