How Could My Friend Be the Demon King?

Accept every precept and devote yourself to the Supreme.

The Supreme: I don't think you're devout to me at all. You just have no worldly desires.

After taking her vows, the first trial is to become a hero and defeat a randomly chosen demon king. Alexandra, a mage by profession, confidently turns down the help of her friend Ethan, a paladin.

Alexandra: A mage should act like a mage.

Not being good at close combat, the mage draws a summoning circle instead. The instant it's complete, her upright and valiant paladin friend disappears and appears in the center of the circle, looking like a creature of darkness. Darkness devours everything around them. The demon king across from them and his castle are reduced to ashes.

In the midst of the darkness, only Alexandra remains unharmed, shining brightly.

Alexandra slowly types out a question mark: You're such an upright paladin. How could you betray us?!

Ethan, who is both the God of Light and the God of Darkness, with two faces in one body: ...I switched accounts by mistake.

Theme: Treat others sincerely.