Old Demon Che was a grade 10 Demon Beast with cultivation at a Deity Transformation stage and the Lord of Myriad Demon Valley. He was also the descendant of an ancient demon from the Spirit Realm. His lifespan was much longer than other demon beasts. He was also an acquaintance of Ling Long.
Old Demon Che has managed to survive so long, because all of the human Deity Transformation cultivators found it too troublesome to hunt him down. They made an agreement. Humans allowed him to found and expand the Myriad Demon Valley, but his true body wouldn't be allowed to leave the valley for no good reason, and that he was strictly prohibited from the widespread slaughter of humans. Otherwise, all human Deity Transformation cultivators would join forces to kill him.
Invasion of North Night Palace
From Ling Long's information Old Demon Che learnt the location for a spatial node to to the Spirit Realm was in spatial tear inside North Night Palace's Spirit Void Hall. About 10 years after events on Kunwu Mountain, Myriad Demon Valley attacked the North Night Palace together with Ice Sea Demons.
Old Demon Che's incarnation led the invasion. With his lifespan coming to and end, he was willing to take greater risk. Many low-grade demons were slaughtered under the effects of the Sea Calming Bell. Myriad Demon Banner was used to attack the grand formation. Ice Phoenix Feng went into the fray, she faced Bai Yaoyi and Overseer Elder Yi. After few days of assaults, North Night Palace cultivators had retreated into the Spirit Void Hall for protection. Later, demon beasts have stormed into the main hall of our Spirit Void Hall with Ice Phoenix Feng's spatial powers.
Later, in the main hall of the Spirit Void Hall, Old Demon Che trapped few Nascent Soul cultivators with his Myriad Demon Banner, while Ice Phoenix Feng battled Palace Master Liu. At some point, a cultivator run into the demonic Qi space. When that person used Triflame Fan, he recognized him as Han Li. He knew from Corpse Xiong what happened on Kunwu Mountain and that Han Li had a connection with Ling Long. Old Demon Che wanted the Eight Spirit Ruler and everything else that Ling Long left. Han Li just wanted to leave through teleportation formation. When Che didn't have an intention to let him go, they clashed in formed demonic Qi space by the Myriad Demon Banner. Despite barrage of attacks using the Great Puppet, Great Yin Trueflame and the Eight Spirit Ruler, Old Demon Che defended himself with the Myriad Demon Banner. Because of innability to defeat him, Han Li escaped from the demonic Qi space to outside with the Worldbreaker Talisman. Old Demon Che tried to entrap Han Li again, but youngster sent the Unbreakable Cinque Devils to deal with him. After Han Li and Ice Phoenix Feng disappeared in the ancient one-way teleportation formation, Old Demon Che clashed with Palace Master Liu and Infernal Ghost Mother. After the Palace Master understood Old Demon Che was looking for a spatial node in their North Night Palace, she detonated the Spirit Void Hall, destroying the spatial node in the process.
About 200 years later, Xiang Zhili discovered a better spatial node located in the Five Dragon Seas and he entered it together with Eccentric Feng, Hu Qinglei and Old Demon Che. Their primal soul lanterns they left behind were extinguished. It was unknown whether they successfully ascended to the Spirit Realm or perished.