Alien Phenomenon Oblivion.
Zheng Yichen used to be able to observe Oblivion without being affected, as he was within the safe zone of Dusk, but now, the Oblivion unleashed by Phenomenon attack doesn't have such a safety range.
Darkness enveloped everything; there was no twilight glow from the sun on the verge of exhaustion, no shelter from Dusk. In this complete darkness, Zheng Yichen instead saw the lower half of the Ancient Venerable 'clearly'.
The lower half of the Ancient Venerable naturally resisted Oblivion in this environment, but when Zheng Yichen reproduced the Oblivion impression, he himself was affected by Oblivion.
The source of this Oblivion was him, so he felt compelled to perfect the Oblivion.
