I'm thinking there were some additional shenanigans going on when Zerofuku and Buddah first met. If I'm reading the Hajun's poem correctly, both Buddah and Zerofuku may have had the potential to meet the requirements to awaken him. The whole theme of Puberty equating to Enlightenment and the merging of Light and Dark seems to add up to this.
Someone may have been tailing Buddah as a candidate initially, before turning their attention to Zerofuku who, according to Buddah, may have been on the edge of Enlightenment when they met. So when Zerofuku became corrupted, that may have been when the individual took actions because that's when Hajun's horns show up on him.