Among the memories that had tormented Zenith's heart from a very young age, the incident in the mountain shrine was the first one that transformed the innocent child inside him in the path of becoming a ruthless devil.
However, while growing up, those scarred memories from the past were one of the reasons why Zenith sought sleeping pills, drugs, or multiple sex partners just to get rid of the insomnia that was followed by his dark past. However, after turning into an addict for sleeping pills, a few parts of his memories were distorted and had completely slipped out of his mind.
The main reason Zenith was hesitant to follow Kylian to the temple was because this place stood as the symbol of his first sin, which he tended to avoid visiting on their first date. It was one of the events from his tainted past which he didn't want to reminisce about, at least not today.