His little darling's last hope was his promise to return after he finished helping his brother. To come back to his side and accompany him in that darkness and maybe a bit of warmth from his hugs which his Jing'er loves. Which in the end, he failed to fulfill.
Ye Xiajie can only watch the point of view of the God of End in his memory. On the day the Vearth was completed and the same day he decided not to return to the Abyss was also the day his Jing'er completely lost it. Not only his heart but also his mind broke. He completely lost his trust in other people and... He was slowly dying inside.
The God of End had witnessed how his little one had become brokenhearted. He started laughing while crying. Shouting as if he was out of his mind and lost his voice for a few days. Finally, losing his sense of pain in all kinds of forms regardless of whether it is dealt physically or mentally. Jing'er became numbed towards pain.