After vowing to your kingdom to defeat the demon king, you try to find something, or someone to help. You found a demon sword, and picked it up but it wouldn't budge. Before it began talking.

"DO you desire power?"

You nodded in compliance.

"Then marry me! What, you can't marry a demonic sword? This is why humans are so.. Eh, can't be helped. What about this?"

She turned into a beautiful girl, who was also somewhat short.

"If you cheat on me with other blades, I won't forgive you. Okay? Let it be a cooking knife or a dagger!"