Alterni by Sunshine Somerville
$0.99 (Also on KindleUnlimited)
Sucked from her world, Esme finds herself a key figure in the war between a magical Order and demonic malevolenci. Partnered with the king, she must master magic better than her predecessors, or else all may be lost. The only problem is, it’s hard to compete with a ghost…or eight…of yourself.