Farming with 5* 2.60
Actually got both Elena and Khagan. I was leveling Elena to 5* 2.60 only, to help farming- I already have Azlar and Marjana parked at 5* 2.60 which is still more powerful than a 3* 3.50 .
Class Quests
But Elena is a fighter, and for fighter class quests I already have Boldtusk and Gryphonkit- my wife- has Delilah.
But for Ranger class quests I have Tiburtus- who is the only Ramming Pulverizer with Pierce so I am taking him to 4*+19 - and Chao- that I want the Devs to buff to 50% mana reduction.
So I am taking Khagan to 5* 2.60 since red does double damage against green mobs & bosses in Nature quest and Serenity quest. But mostly for the defense buff to keep alive Tiburtus and Melendor 5*+4 / Aegir 5* 2.60 for class quests.
Slow mana speed and class quests
I have noticed for class quests that, if you are missing 2-3 colors, slow mana speed heroes are often as good as fast mana speed heroes because you waste so many matches with no mana for any hero on your team. Cute move by the Devs.