"Assaulting the Lair of Nightmares..." The very audacious plan seemed increasingly viable as the sprites discussed and Hao Ren, as well as co, thought it out.
Every impregnable citadel was easier to destroy from within than without. Now, if they could send an elite team into the Lair of Nightmares and decapitate the monster in charge of creating the corrupted army, everything would be resolved.
As Hao Ren needed the crystal of Amantir regardless, that meant he had to find a way to get rid of the Lair of Nightmares because it was connected to the crystal.
The best route to assault the lair was from underneath: Blowing up the crystal pillars that supported the crust would affect the Lair of Nightmares' structure, and according to the sprites' calculations, it would be enough to tear the lair in half.