Death Temptation

The Undead Plane was so terrifying mainly because of the endless numbers of the Undead. One could attack until their hands went limp from exhaustion, and they still wouldn't be able to kill them all. In Noscent's history, expeditions to the Undead Plane hadn't happened just once or twice, but countless times. However, the Undead Plane had only been conquered by a handful of individuals.

The rest all died in there, and most of them didn't die in battle, but from mana or stamina exhaustion.

It wasn't as if everything would be fine if they flew up just because the Skeleton Warriors couldn't fly. There was a large group of Skeletal Wyverns in the sky numbering over ten thousand. There were so many that it was impossible to count them all. If a Heaven Rank powerhouse was attacked by all those Skeletal Wyverns at once, even if they didn't die, they would still be injured.