Broken Dragon (The Chronicles of Mara Lantern, Book 3)

After agreeing to share his body with the consciousness of a dragon from an alternate reality, Ping—Mara Lantern’s friend and mentor—loses control. The creature senses danger and begins to rampage across metropolitan Portland, stalking Mara’s mother.
So busy fending off attacks, Mara doesn’t have time to figure out why her niece came from the future, or why people who crossed over from other realms are mysteriously disappearing. And if all of that wasn’t enough, Mara still isn’t sure if her friend Abby was actually turned into a metaphysical demon.