Iron Angel — S.A. Welsh

Brett is a government scientist on the run because the people he works for want to use his research about realms and other worlds for their own gain. He escapes with the help of his uncle, only to find a man falling from the sky in a ball of flame and feathers after being shot down by the very people he himself is running from.

Iron is a warrior guardian to the rightful king of Angelum, but was forced to flee his home realm with his king after a coup for the throne. There is a bounty on his head and the last thing he needs is to be almost captured by the human military that want to cage and experiment on him.

Iron cannot resist the tempting human that saves him and, when they give in to the heat between them, they accidentally trigger the irrevocable mate bond. Both of them are running from something, but they may just discover that each of them is exactly what the other needs.