Ice Phoenix Feng was a grade 10 Demon Beast from Ice Wave Island, a home of Ice Phoenixes. She was restricting her cultivation base to the peak of late Nascent Soul stage, because she was afraid of creating an imbalance in the Mortal Realm's origin Qi.  
Before Fairy Ice Soul ascended to the Spirit Realm, she froze over the Ice Depth Mountains for over a hundred years. Ice Phoenix Feng wanted to exterminate her line of cultivators in the Mortal Realm. Anyone who also had inherited Fairy Ice Soul's Celestial Ice Flames was a sworn enemy of the Ice Phoenixes.
Invasion of North Night Palace
When learning that Myriad Demon Valley was attacking North Night Palace because of a passage to the Spirit Realm, Ice Phoenix Feng joined them. Old Demon Che's incarnation led the invasion. 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.
As Ice Phoenix Feng battled Palace Master Liu and 2 Elders, she noticed Han Li coming out of Old Demon Che's demonic Qi space. She was willing to ignore him, if he didn't get involved in a battle, but when she noticed him using purple ice flames on his way to teleportation formation, she assumed he was from North Night Palace too and she attacked him with fury. Her white ice flames were stronger than Purple Apex Flames. Then Old Demon Che tried to entrap Han Li again, but the later sent the Unbreakable Cinque Devils to defend himself. As Han Li was facing Ice Phoenix Feng, Palace Master Liu joined him and summoned Infernal Ghost Mother. Han Li decided to use chaos and just leave through teleportation formation. Palace Master Liu wanted to stop him from leaving. Infernal Ghost Mother was scared away with Buddhist Eight Spirit Ruler. Despite Ice Phoenix Feng still trying to kill him, Han Li disappeared in the ancient one-way formation together with Ice Phoenix Feng.
Visiting Scattered Star Seas
After ending up in a sealed chamber, Ice Phoenix Feng escaped using her spatial powers, but she couldn't leave the building, because they were in the Heavenvoid Hall. After being unable to find exit, they decided to work toghether. When it was necessary for Ice Phoenix Feng to use Han Li's the Heavenvoid Cauldron, he changed his mind and decided to just wait, till the Hall will open again.
After 80 years, Han Li reached late Nascent Soul stage to Ice Phoenix Feng's enormous suprise. Then they used the control formation and forced the Heavenvoid Hall to appear. When they appeared outside the Hall, Old Devil Hun at Nascent Soul stage approached them, because he thought a valuable treasure appeared. Ice Phoenix Feng killed him easily out of frustration. Then she left to search for a way back to the Great Jin.
Leaving the Mortal Realm
Ice Phoenix Feng reached the Deity Transformation stage. Later, she learnt about the spatial node to the Spirit Realm from disciples of the Heavenly Devil Sect. After arrival at it's location in the Five Dragon Seas, she met Han Li there. At some point, the demon beast bestowed a few drops of her glacial essence upon Tian Qin'er, which cured her from Dragon Cry Physique. After 100 years of waiting in total, Ice Phoenix Feng and Han Li entered the spatial node. She used her Heaven Puncturing Ark treasure for protection. When they exited on the other side, they had been forcibly separated.