Zero Kirisame/Relationships

Killer Queen
Killer Queen falls hopelessly in love with him after he saves her from some satanists.

Tron
After he saves her life, Tron becomes very loyal to him and by extension, Hakuto Kunai.

Hakuto Kunai
The most hated man in the Grand Empire, was not shown an interaction of the two but due to his hatred of the Grand Empire he is probably his greatest enemy.

Oono Akira
Akira was its creator, after being dragged into the new world, Akira experienced the bitter taste of seeing his creation gain awareness.