In ancient times, Zun was quite arrogant. When he traveled from the west to the Divine Land, he was ambitious and wanted to dominate the place. However, reality shattered his self-confidence. Not only did he fail to meet his goal in this place, he was beaten up like a dog by the people here.
When he came to realize that the masters in the Divine Land were much more powerful than him, it was too late for him to follow their path. He was just as weak as an ant in the eyes of the masters.
Since he finally saw a powerful figure that would arise in the future, naturally he would want to show his loyalty to Jacob quickly. He couldn't miss this opportunity to be the follower of a big shot like he had in the past.
"I said to call me 'boss', not 'master'. We don't use that anymore." Jaco
