Wind lesser is pretty bad, most of use Ether transform his 5* version in order to get a Wind Archangel.
6 Fire demon hunter is pretty much a cheaper version of Water Mafia but still does the job pretty well if you dont have an aoe defense debuff.
6 Water lady is a very good unit in order to take out tanks that are using Taunt/Absorb (or even both!).
As for Kampanu, the idea of focus is nice but the fact that it only last 1 turn makes it less viable as you need to make sure to deal a ton of damage in order to kill the focused units. (Pray that the enemy team doesn't have an awesome healer, which is highly unlikely)