Blood Red Moon - Worlds of Fire

Out of the ashes, a new beginning... When his family and most of their kind were destroyed by the Guild, Derek inherited the position of Vampire Lord. In the old world Derek came from, peace existed between all beings. There, Alchemists held the keys to creating portals to other worlds, knowledge they passed down to phoenixes. Their utopian society was crushed when the Guild invaded, intending to unlock the powerful secrets phoenixes possess.
Derek and Avani met the night their city was sacked and fell in love. After the city succumbed, they were lost to each other. Love will be resurrected in blood and fire.Having lost her memory, Avani became a protégé of the Guild Master, conditioned by magic to believe shifters and vampires were evil. Eventually, she was made Seeker, tasked with finding the Vampire Lord in order to gain access to phoenixes.
A Vampire Lord has a special bond with a phoenix. During a vampire's time of fertility, the phoenix's energy is triggered, allowing her to transform and open the portals. When Derek finds Avani, he neutralizes the magic that's kept her from remembering who she is. Together, they flee into The Borderlands, where he and his allies can protect her. However, the Templars in the city have almost certainly made a pact with the enemy of all supernatural creatures, granting them use of the portals.
Only a phoenix can save the world from utter ruin now, but that was precisely the asking price.