The Two-Faced God by I. T. Lucas

In a world where dragons dominate the skies and colossal worms tunnel through mountains, three nations teeter on the brink of war.

Like every Elucian, Kailin must brave the perilous pilgrimage to Mount Hope’s summit, where an ancient shaman will decide her fate. A select few are destined to bond with dragons, and for most, it’s the ultimate prize. Not so for Kailin, who is hiding a paralyzing fear of heights and would rather sketch the magnificent beasts than ride them.
Alar appears to be a privileged Elurian seeking the glory and immortality of dragon riders. Yet beneath his aristocratic facade lies a secret agenda that could disrupt the delicate alliance between the reclusive Elucia and the cosmopolitan Elurian Federation.
When Kailin and Alar cross paths, sparks fly, and as they ascend the perilous mountain, hunted by shadowy assassins and tested by ancient rites, their unlikely bond deepens.

Defying a thousand years of tradition, an impossible selection puts the star-crossed lovers at the center of an ancient prophecy. But in a world where dragons have their own agendas and even the gods aren’t what they seem, the greatest threat may yet come from within.