Grandmaster Duel

 is an Imperial Legion quest in.

Background
In order to achieve the highest rank in the Imperial Legion, the Knight of the Imperial Dragon, the Nerevarine must defeat the current Knight of the Imperial Dragon, Varus Vantinius, in a battle in the Arena in Vivec City.

Quick walkthrough

 * 1) Speak with Varus Vantinius in Ebonheart
 * 2) Defeat him in a duel in the Arena at Vivec

Detailed walkthrough
After the Knight of the Garland rank is reached, Varus Vantinius can be asked about an advancement, to which he will reply that the current head of the Legion, he, must be defeated in order to become the next. The battle in the Arena may be difficult, since the two artifacts given to Varus in the previous quest are still in his possession. After killing Varus and effectively becoming the leader of the Legion in Vvardenfell, the Lord's Mail and Chrysamere artifacts can be looted from his body. In addition, upon completion of this quest, the Imperial Legion uniform will not be required to speak with legionnaires anymore.