DreamWorks Dragons: Legends of The Nine Realms

Challenge Difficulty is unlocked on a level after you have done both the blue and orange routes in a level. You can level up your dragons to be far stronger before attempting to make them easier. This achievement is for completing challenge on all five levels in the fourth world called Dark Realm. This is where things started to get a little more difficult. Level four was the hardest. Skip all enemies unless in a zone, and exploit enemy’s weaknesses. I had two dragons maxed out and the other two around 30% leveled.