"Roar of the Sky" by Calla Zae.

Book 1 of the Infinara Dragon series.

Special Edition Hardcover includes: 

1 - Special Edition Hardcover

• Foil Cover
• Printed Edges
• Novelty End Pages
• Two-Page Character Art
• Two-Page Chapter Art for Male POV
• Two-Page Chapter Art for Female POV
• Two-Page Bonus Scene Art
• Dragon Bonus Scene

Details: 

Love never crossed his mind until she cut into his life like a gleaming sword, slicing through his stern facade.

Hardened by heartache and too many bloody battles, General Wen Hung is focused on protecting his land and nothing more. When a beautiful healer uses a unique skill to save him from a deadly attack, she shifts something inside his heart. Now, he wants something that both terrifies and comforts him.

Determined to pave her own path, Zhao Mei Su is a talented healer with the passion of a warrior. But she has no teacher to educate her until she dares an adept warrior much older than her to give her lessons. The more she practices, the more her energy field transforms, connecting her to a cosmic realm she never knew existed. When a dragon roars for her, confusion and wonder set in as the unavoidable battle between the dark and the light erupts.

As darkness intensifies around them, Su and Hung join forces with the dragon realm to protect something more precious than they could ever imagine.

This is Book One in the Infinara Dragon Series.

If you enjoy tropes such as age-gap, slow burn romance, morally gray alpha, mentor/mentee, found family, magical bond, happily ever after, and C-Dramas, then you'll enjoy this book.