Siegrun, also known as Sigrun, serves as an Einherjar—a magic-wielding warrior—within the Wolf Clan. She possesses long silver hair typically tied in a ponytail, red or purple eyes, and attire reflecting Yggdrasil's setting.

Initially dismissive of Yuuto Suoh, the Wolf Clan patriarch, due to his perceived physical weakness, her attitude transformed into unwavering admiration and fierce loyalty. She formalized this bond as his sworn daughter through an oath ceremony, becoming his primary bodyguard.

Her personality blends strong-willed honor and a warrior’s code akin to Scarfior’s. She exhibits fierce protectiveness toward Yuuto, initially craving his praise before developing deeper romantic feelings. Less verbally expressive than clan peers, she conveys devotion through decisive actions. In victory, she displays composure and magnanimity toward defeated foes.

Prior to the main events, she evolved from skepticism about Yuuto’s leadership into one of his most steadfast defenders. This loyalty sparks aggression against perceived threats to him or losses of cherished items. Yet during combat, she prioritizes tactical responsibility over emotion, retreating when overpowered by adversaries like Steinþórr or unable to safeguard her cavalry.

She wields a katana gifted by Yuuto. Her rune, Hati or Mánagarmr ("Moon Hound"), enhances her physical strength, drawing from Norse mythology’s wolf destined to devour the moon at Ragnarok.

Available media omits her origins and family history. Documented traits include a birthday on April 3rd and greater comfort with nudity during communal baths compared to others.

Her character development navigates tension between deepening affection for Yuuto and disciplined warrior ethics. She suppresses personal desires if they risk endangering others, reflecting her ongoing struggle to reconcile emotional vulnerability with duty.