How do you get Dian Weis level 11 weapon in Dynasty Warriors 4 Extreme Legends?

Defeat Hu Che Er after he appears.

Defeat Jia Xu after he appears.

Achieve 200 KO Count.

I strongly suggest eliminating all the enemy arrow soldiers first, because not only are they a nuisance, they are also lethal. Always defeat the constantly reappearing entry point captains first, they give you much needed temporary in-game items. Saving after receiving the weapon learned message is recommended, because it will be a struggle getting Cao Cao (and Dian Wei) out of this mess alive. Do this on Expert mode