Rise of a Necromancer: Mages and Magic

Rojo Siete Φωτιά
The red dragon full of chaos fire magic must serve the human mages for seventy years.
Leslie Μάγος
Orphaned human child of slaves, sold to the Magesterium to train as a mage, and paired with a fire dragon.
Ruven Σκιά
Shadow assassin elf turned tracker with a hellhound who eats the undead.
Heista Νεκρός
An undead priest risen and controlled by the most powerful necromancer

Tiamat is a demon god from Earth now banished to a world full of magic and dragon. Lucky for him, his dragon form is a six-headed dragon. The magic here is not like on Earth, it comes from dragons, not from souls.

To be a god on this world, he must learn how to harness the power of the dragons. So, pretending to be less than he is, he joins the Magesterium to train as a mage. He masters this ability easily but is paired with a dragon who was once a human. Her dragon mate has died and if he doesn't pair with her, the other dragons will kill her.

Her magic is weak, but Tiamat can fix that. He can show this world that the dragons banished from their clans can find a new purpose, just like him. Until his past catches up and demons from Earth arrive to take a soul from Tiamat that they feel is theirs. Turns out, necromancy is easy to do on this world and the other demons have no qualms about using it.

To defeat the other demons, Tiamat must give up the new life he's found, and become the god he was destined to be.

This story is told from multiple viewpoints and is available in both an all-ages friendly adaptation (Mage & Magic) and the original (Mages and Mates) which has a heavier focus on romance.