The Battle Royale based 72 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.
There's a literal example during the Battle of the Everfree, as the most powerful being in Titan's monster army is Exakktus the Black, the most ancient of all dragons. At least, until Fluttershy talks him into switching sides.
Destroyah in The Bridge plays this role to Xenilla, abet very begrudgingly. She knows she is powerful enough to dethrone him, wishing to do so by the first chapter; but a shred of loyalty over a yet unrevealed event keeps her from doing so at the moment.
Queen of All Oni: Ikazuki to Tarakudo, as per canon. And when he temporarily takes control of the Shadow Hand, he forcibly demotes Jade to being his dragon — and the only reason she has a relatively high position is because he looks down on the human members even worse than he does on her.
Co-Dragons: Left and Right, being Jade's top Shadowkhan, arguably qualify for her Dragons. Hak Foo, being the heavy muscle, could also count (though he's more of The Brute), as could Jade's foreman (first Valmont, later Blankman).
Though once Hebi shows up, her status as General grants her the position and demotes the others.
Hiruzen was this to the Oni Elders, apparently serving as chief General and advisor.