A savage relic of Dark Age terraforming, Lacusta is split between equatorial savannahs and polar jungles, stalked by colossal reptilian predators. Human tribes survive by taming these beasts as war-mounts, forging a culture of blood-feasts, beast-bonds, and fatalistic courage.
To the clans, Imperial Guard recruitment raids are the descent of “sky-lizards” that devour whole villages. Those taken become Windrider regiments—feral shock cavalry who charge into battle on reptilian mounts with suicidal abandon, wielding warhammers and clad in scale-like armor.
Imperial presence is minimal; the tribes are periodically harvested. Strategically, Lacusta offers little but manpower—yet its Windriders are feared and admired across the Drusus Marches.
Ignis Aeternus WH 40K campaign notes 