Frogface

From Glen Cook Wiki

Frogface is an imp, a magical being summoned from another plane of existence. One-Eye purchases him at a shop in Gea-Xle, much to Goblin's irritation; Frogface is a powerful trickster and spy who greatly enhances One-Eye's ability to pull pranks on Goblin. Frogface is named after Goblin, who he resembles. Frogface stands two feet tall, with the proportions of an adult. He is able to teleport from place to place and perform basic wizardry.

The imp is in fact planted by Soulcatcher, which perhaps One-Eye ought to have known - Smoke, a wizard who is superior to One-Eye in talent, skill, and training, says he can neither control nor summon such a thing. Frogface helps spy on the Company for her and assists her with her convoluted scheme to kidnap Croaker once he and the Lady declare their love for one another. He also helps Croaker reattach Soulcatcher's head. Frogface tells Croaker that Soulcatcher can sentence him to an eternity of torment with just one word, and says that mortals "have it easy" because they can at least die eventually.

After Croaker is kidnapped, Frogface abandons One-Eye. He continues to spy for Soulcatcher, and does her a major favor when he frees her from a magical sleep after she is captured by the Shadowmaster Longshadow and The Howler, who mistake her for the Lady. In gratitude, Soulcatcher agrees to free Frogface after he helps her get away from the fortress at Shadowcatch and elude the monstrous shadow which Longshadow summons to hunt her down.

Interestingly, while all the knowledgeable sorcerers call Frogface an exceedingly dangerous entity capable of scything through regiments of soldiers, he is apparently forbidden to take life, a stricture exceeding even Soulcatcher's control over him.