Love For His Kind by Margery Ellen

Lazarus MacEachen is on a mission. He has gone to the frozen north to save the Alicorn and the dragons that still survive there. In a battle with Baudwin, he is gravely wounded.
Dofri must take up his father’s sword and finish the battle. In an attempt to save his father, Dofri transforms into an entity no one has seen for thousands of years. Only one person knows the meaning of this change.
The Alicorn, guardian of the Fae and the shifter world, is near death, sealed in a freezing tomb within Brickended Fortress. If she isn’t rescued soon, peace will never return to their worlds.
Will Lazarus survive? Will Dofri understand what he has become, and will the Alicorn be rescued in time?