Humans Don't Make Good Familiars

Suma, a mage from another world, accidentally summons one of the most powerful familiars her world has ever seen... a normal British teenager. Born with a natural affinity for Chaos-Magic that manifested itself once entering her world, Jake becomes a caring friend to the young mage, and a formidable enemy to anyone who may dare hurt her. But Suma's world is plagued by war, and Suma has been drafted.