Stags is a male Invectid insectoid, initially one of Lord Mantid's top generals within the group called the Big Four. He possesses formidable combat abilities and unwavering loyalty to the Invectid cause. His imposing stag beetle-like form features prominent horns, and he wields a large zanbato sword as his primary weapon.

He adheres to a strict code of honor, showing respect to adversaries deemed worthy, such as allowing Corona and Igneous to retreat unharmed after a confrontation. During the invasion of the human kingdom of Nuuma, Stags served as lead commander until Lord Mantid stripped him of this role due to perceived failures in securing the Oracle Keys. A subsequent duel against Hunter Steele and the battle spider Shadow resulted in significant injury, including the loss of one horn, triggering a crisis of confidence and leading Stags to exile himself from the Invectid forces.

Following his exile, Stags wandered Nuuma. Witnessing Buguese's confrontation with Mantid reignited his warrior spirit, prompting him to aid Buguese. He later joined forces with Beerain and Buguese to protect the Spider Riders from Mantid's attacks. In the final battle, Stags assisted in delivering two Oracle Keys to Hunter Steele, facilitating Mantid's defeat. After the conflict, Stags observed the restoration of sunlight to the Invectid lands alongside his former comrades.

A production detail notes that in the Japanese version, extended bouts of laughter were a recurring trait for Stags, though this characteristic was reduced in the English adaptation. His character design also limited mouth movement during dialogue sequences.