Dilgear is a hybrid creature, being a half-beastman and half-troll, who appears as a subordinate to the powerful mage Rezo the Red Priest. He is initially placed under the command of Zelgadiss Graywords, Rezo's great-grandson and a chimera, serving as one of several mercenaries in Rezo's organization. Dilgear has a humanoid body covered in fur, with a wolflike head featuring a snout and pointed ears, as well as a short tail. He typically wears a tunic secured with a belt and light leather armor covering his upper chest and shoulders.

In terms of personality, Dilgear is notably violent and aggressive during combat, willing to go as far as killing his foes directly. This stands in contrast to some of his fellow henchmen like Zolf and Rodimus, who are more reserved. Despite being placed under Zelgadiss's authority, Dilgear's ultimate loyalty remains with Rezo himself. This allegiance becomes critical when Zelgadiss breaks ties with Rezo, at which point Dilgear turns against the chimera without hesitation.

Dilgear first appears pursuing Zelgadiss, Lina Inverse, and Gourry Gabriev on Rezo's orders. In an early confrontation, he finds himself outmatched and is forced to retreat. He later ambushes the group in an inhabited town with the help of several trolls and other creatures. During this second battle, Dilgear believes he has been saved when Zolf and Rodimus arrive. However, contrary to his expectations, these two declare their loyalty to Zelgadiss rather than to Rezo, and they attack Dilgear instead. Zolf wounds him severely, and Dilgear falls with the defiant final words that he will come back to life.

His claim proves accurate due to his hybrid nature. The troll half of his heritage grants him a powerful regenerative ability that allows him to recover from injuries that would be fatal to most beings. Dilgear does survive and later reappears. In some versions of the story, he returns as a bounty hunter sent alongside Rahanimu and Vrumugun to eliminate Lina Inverse and Gourry Gabriev, though he is quickly defeated again.

The most unusual turn in Dilgear's story occurs in the light novels and manga continuations after the defeat of the demon lord Shabranigdu. With no purpose or place to go, Dilgear wanders into the kingdom of Zephilia and collapses from hunger. There, he is discovered by Luna Inverse, Lina's older sister, who has a habit of feeding stray animals. Luna takes him in, but when Dilgear wakes up, he finds himself chained inside a large doghouse in her backyard. To his horror, Luna renames him Spot. Although he is humiliated by this treatment, Dilgear feels a sense of loyalty to Luna for saving his life and ultimately remains as her pet. This fate has led some fans to mistakenly identify Dilgear as the beast form of the greater mazoku Zelas Metallium, though no actual connection exists between the two characters.

Dilgear possesses no magical abilities of note. His primary assets in combat are his physical strength, his skill with a sword, and most significantly his troll-derived regeneration, which allows him to recover from wounds almost instantly. These traits make him a persistent nuisance to his enemies, though his actual combat ability is not exceptional enough to pose a serious threat to powerful opponents like Lina Inverse or Zelgadiss. His role in the story is that of a recurring minor antagonist whose violent temperament and misplaced loyalties ultimately lead him from serving a powerful priest to an ignoble but peaceful existence as a domesticated pet.