Wallenstein/Relationships

Nagi Arisuin
Wallenstein's former student who he held in high regards upon noticing her potential as an assassin despite her age. He was distraught and enraged after noting her sudden change due to Nagi not going along with the plan of destroying competitors for Hagun Academy who Nagi had also grown close to, as Wallenstein had even started beating and stomping on her while being tied up in front of her, then started to fight Shizuku in front of Nagi.

Shizuku Kurogane
As Shizuku is among Nagi's closest friends at Hagun Academy, possibly viewing her as the cause of his student's sudden change. He had mercifully fought against her causing serious wounds such as cutting off her arm and he had also cut her in half at the waist in front of Nagi to cause him to despair. Though after Shizuki utilized her new Noble Art, Aoiro Rinne against him causing Wallenstein to become afraid after being suffocated by water he later seemingly died in front of them.

Or-Gaule
Wallenstein inspired Or-Gaule to join Rebellion as a child, but he had later shown to be annoyed about his child-like personality, as well as despising him after killing almost all the members of Rebellion and their Numbers. He also felt annoyed that Or-Gaule has gotten cocky due to him being a desperado.