The Substitute Dragon King

The Dragon King, Aurelius, is attacked and disappears. His identical twin, Jin Long, a food delivery boy, is mistaken for Aurelius and thrust into his world, becoming a target. Stella Sinclair, Aurelius's fiancée, brings Jin Long into the Sinclair Family as a live-in son-in-law to replace the Dragon King, to solidify her family's position. Jin Long endures oppression, but evolves to become the new Dragon King, inheriting his brother's mission to protect Auria.