Sci-Fi Space Dragons

Read this book as a kid, think it was a series.

Basically had a Space Dragon Alien thing and a Human as the main two characters, and a third Alien race that has like... a frickin death beam thing that kills anyone it's pointed at but it turns out it doesn't work when a Human and a Dragon alien thing are bonded together.

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Also the dragon may have turned into Tattoos on the human? Might be combining it with the Heron brand from WoT in my head but I'm fairly certain that happened.