Honestly half of it is based on vibes and speculation, but basically:
Victim - seer of hope - gains knowledge through hope, uses said knowledge to aid others. Hope, I feel, describes Vic pretty well. “Driven first and foremost by convictions” “They put great value on creativity and the ability to dream up a better future” (Rocketcorp arc) “They aren’t adverse to a little destruction, especially if they think they can replace it with something more just” honestly these all just speak for themselves. Very Victimcore
Mitsi - sylph of heart - heals souls and people’s sense of self. Mitsi played such a big part in Victim’s healing journey and helped him discover parts about his identity and wield them to his advantage. Literally healed his soul.
Agent - knight of life - protects life, uses life to protect others, wields life. Agent is obviously a very caring person, he cares deeply about Victim and Mitsi and he does anything he can to protect them. So the title of Knight of Life is fitting for him. He’s not afraid to use other’s or even his own life in battle to protect the ones he cares about.