Knights-Vexillor are the standard-bearers of the Stormcast Eternals, proclaiming their hatred for chaos and Sigmar's intent of reclaiming the realms. But these standards are more than just icons, they blaze with the glorious light of celestial energies, which they can call on its powers in battle.
Knight-Vexillor are not chosen by their reforging but to prove they can protect the sacred relics they carry they must prove themselves in the gruelling arena combats of the Gladitorium where only a single champion may emerge victorious in a contest of arms. 
The duty of the Knights-Vexillor to bear the holy banners of Azyr into battle. These are crafted by mystical arts Azyrite saints and their power can be unleashed to both empower allies and summon the wrath of the heavens upon the enemy.
Some carry a Meteoric Standard, able to pull comets from the stars to smite foes with blazing heat, while others carry the Pennant of the Stormbringer, capable of summoning hurricanes to transport the Stormcast across battlefields. They also carry Warhammers into battle, in case they need to defend themselves.
The most glorious among them are the Banners of Apotheosis, made of starsilk threaded with swarf and shavings of the Anvil of Apotheosis and blessed by both Sigmar and Grungni. These are carried by Vexillors in Thunderstrike Armour and when proper litanies are intoned the banners nearby Stormcasts are bathed in the light of the forge causing their flesh to harden as sigmarite while damage to their armour is miraculously restored.
- 1: Warscrolls
- 2: product description
- 3: White Dwarf Vol.3 No 30, April 2019: The Tome Celestial, pg. 48
- 4: Battletome: Stormcast Eternals (2018) - Knights of the Stormhost - pg.68
- 5: War at Amberstone Watch (booklet) - Knights-Vexillor, pg. 12