Ze Strait acts as both personal secretary and lover to Hell Deathbird, military commander of the Ocean Empire. Her allegiance to Deathbird is absolute, persisting even as he launches a coup against Queen Ze Violencia, rightful ruler of the Water World Men (Oceanides) – Ze Strait's own people. She actively supports his ambitions to control the oceans and facilitates his rise within the Empire, motivated by a blend of genuine devotion and a desire for power, despite his escalating destructive actions against her kin.

Ze Strait experiences internal conflict and growing despair, particularly witnessing Deathbird cross a Moral Event Horizon by deliberately destroying the Water World Men's underwater kingdom. While warring feelings of remorse for her betrayal and her people's near-annihilation surface, her commitment to Deathbird consistently overshadows them. Her choices lead to profound isolation; she is rejected by surviving Water World Men and viewed as an enemy by surface humans. This isolation deepens her depression and pessimism, as she recognizes her fate is inextricably tied to Deathbird's inevitable downfall.

Despite Deathbird's ruthless tyranny towards others, he genuinely returns her affection. Yet, Ze Strait's loyalty faces its ultimate test. During the final conflict, as Deathbird's flagship submarine suffers critical damage battling the Super 99, she sacrifices herself to save him. Shoving him aside from lethal shrapnel, she sustains fatal injuries. Dying in his arms, Ze Strait uses her last moments to explicitly confess her love and implores him never to forget her. This final act underscores the depth of her devotion, even as Deathbird subsequently destroys himself and his crippled vessel. Her character arc concludes with this self-sacrifice, cementing her role as a tragic figure consumed by misplaced loyalty and love within the Ocean Empire's conflict.