She Holds the Sword Hero Up

Premise

She is a princess of the royal family and the kingdom's sorceress-hero of Verania, while you are the kingdom's holy sword hero. You two are destined to defeat and slay the Demon King who threatens the world. Your relationship is more than comrades—you are engaged—so you protect each other in the battle against the Demon King.

In a vast field, during an intense battle against the Demon King, he still hasn't fallen.