The Battle Royale based Seventy Two Hours has Mike V as this to Joel. The latter is the head of the wrestling club who are rampaging throughout the island, torturing and killing anyone getting in their way. The former is his trusted lieutenant, and one of the few in the class who can claim to be as sadistic as Joel.
The first arc of The Private Diary Of Elizabeth Quatermain has an unnamed invisible man stalking the protagonist on behalf of the Big Bad. The Big Bad doesn't really trust anyone, but this guy comes closest. He's supposed to kill her if he can, but all his attempts keep getting thwarted, so he does the next best thing — lures her to where the Big Bad can torment her.
One of the major agents of the Villain Protagonist's private army, (in the Mass Effect fanfic The Council Era), an asari known as Adaria, serves as The Dragon for the salarian politician, Tyrin Lieph's. Her primary motivation and reasoning for her loyalty to him is My Master, Right or Wrong. She serves as a Co Dragon with the leaders of the other sectors within the Soldiers of Salvation, like batarian Nikhail Baraat and quarian Shedev'Higa.
A Disgaea fic titled Disgaea Jewel of the gods has a knight cloaked in armor named Fried, who is the strongest minion of Baal, and his right hand man, gathering the ingredients to curse Adell, Mao, and Laharl, putting their levels down to 1, and defeating most of the people in Evil Academy for him.
