His Fated Mates by Hawke Oakley

A pregnant omega in mortal danger.
Matheson found love and the true meaning of the prophecy, but that doesn’t mean his struggles are over yet.
After fighting for their love, his relationship with Ramsay, Colton and Eric is closer than ever. Now pregnant with the child of all three of his mates, Matheson has unlocked his true magical potential. With the help of the gryphon Noro, Matheson and his new family must learn to use his powers for everyone’s sake.
But the four packs don’t understand their relationship, or Matheson’s unusual pregnancy–and their problems get worse when an old enemy reveals Matheson’s secret and puts his life in peril.
When the whole world is against them, will Matheson’s bonds with his mates stay strong–or will they break?