Edward Ruby Martínez, second prince of the Malcosian Empire, earns the fearsome title "Bloodthirsty Prince" through formidable battlefield prowess and his unorthodox knightly order that welcomes both commoners and nobles, inciting widespread fear and disdain in neighboring kingdoms. Yet, this reputation masks his true nature. Married to Carolina Sanchez through political arrangement, he reveals unexpected tenderness and genuine affection, openly adoring her alongside his immediate family.

Hints of familial neglect or emotional hardship similar to Carolina's potentially foster his understanding and patience toward her trauma. As their relationship develops, his protective instincts intensify. Post-wedding, he postpones consummation and departs on a months-long campaign to exterminate mana-beasts, inadvertently triggering Carolina’s insecurities. Upon return, he takes her to Count Kissinger’s domain for a honeymoon where shared experiences and conflicts deepen their emotional bond.

Edward’s development features intense loyalty and occasional impulsiveness driven by love. Jealousy over perceived romantic tension between Carolina and his brother, Prince Gilbert, leads him to violently grab her arm—causing bruises—and shove her against a tree. This incident resolves through emotional confession and mutual declarations of love, framed as an expression of overwhelming devotion rather than inherent cruelty.

He becomes central to protecting Carolina from political threats after her divine powers emerge, actively supporting her role in resolving the imperial succession crisis involving Prince Gilbert’s illness. He counters adversaries like Archbishop Mills, who schemes to exploit Carolina’s powers. His commitment to safeguarding her intersects with broader political strategies, including orchestrating public events like the Saintly Trials tournament to secure her position. Their relationship evolves into a partnership marked by mutual reliance and deepening romantic commitment.