Tanjum is Dunlap's foil and antagonist-turned-party-member near the end of the arc

both rep their respective gods, so their ideals constantly clash throughout the arc

Tanjum heavily favors order to be followed, whereas Dunlap views that the individual decides how to follow their own life without a strict means

as Tanjum was raised in within the church of Manea, he was never exposed to perspectives other than that declared by Manea and his followers, therefore his hatred of Dunlap originally stems from never having a perspective other than what he knows, and that wall cracking opens some really tense moments between the two once Dunlap starts getting Tanjum to question why he follows Manea blindly