Sei

Sei (also known as Hobusei or Hob-Sei) is a supporting character in the Re:Monster anime. She is a female hobgoblin (evolved from a goblin) from the generation just before the protagonist Rou (Gobrou).

As one of the rare goblins with strong magical talent, Sei serves as a skilled mage and acts as the commander of the community's magic unit, training other goblins who show aptitude for spellcasting. She is intelligent, level-headed, and knowledgeable about magic, often explaining its basics to Rou early on after his evolution into a hobgoblin. In her downtime, she's typically seen studying magic books, but she's no slouch in combat and can hold her own on the battlefield with impressive kill counts.

In the anime, she's voiced by Aya Yamane (Japanese) and Mikaela Krantz (English). She's portrayed as a calm, bookish "badass bookworm" type within Rou's growing goblin/parabellum group.