Not every Aeldari who takes to a jetbike is an Aspect Warrior. The Windriders are drawn from the Guardians, the citizen-soldiers of the craftworld, who mount the anti-gravity bikes to serve as forward scouts and rapid-response cavalry for the warhost. In this they follow one of the oldest instincts of Aeldari warfare, to move faster than the foe can react and to be gone before he can strike back.
Each jetbike is a sliver of grace and menace, its anti-gravitic motors carrying the rider over any terrain at tremendous speed while twin shuriken catapults set into the hull spit a hail of razored discs. Every third machine in a squadron often mounts a heavier shuriken cannon instead, and a jetbike-borne Warlock may join them to lend psychic aid, so that a Windrider squadron can tailor its firepower to the task before it.
In battle the Windriders embody the serpent-strike so favoured by the Aeldari, and by the jetbike kindreds of Saim-Hann above all. They sweep around the enemy's flanks or drive clean past his lines to fall upon vulnerable rear positions, unleash a sudden fusillade, then gun their engines and vanish before retaliation can gather. Against such speed a slower foe is left forever a step behind, bleeding from a hundred cuts he can never repay.