Chuuya is his enemy, however Dazai enjoys annoying him (childish) and uses him as a piece in his plans since Dazai's planning skills are impeccable and Chuuya's strength and power is undeniable, and due to the compatibility of their abilities and personalities (chuuya was always impulsive and dazai more logical) they were always forced to work together ,even though they are no longer in the same organization, whiny when it comes to chuuya, they trust each other (accidentaly genderbend)