Deff Dreads exist for one purpose: to give the most battle-hungry Orks a way to keep waging war even after their original body has been shattered beyond saving. Encased within a hulking suit of scavenged armor plate bristling with crushing claws and heavy weaponry, the Ork sealed inside a Deff Dread trades mobility and finesse for a machine that can shrug off damage no living greenskin could survive.
Most Orks who end up piloting a Deff Dread do so willingly, viewing the transformation not as a tragedy but as an upgrade, a chance to keep fighting bigger battles wrapped in a bigger, tougher shell than flesh alone could ever provide. Mekboyz who perform the grim surgery required take considerable pride in the work, treating each completed Dread as a walking advertisement for their engineering skill.
An Engine of Spite
What a Deff Dread loses in speed it gains tenfold in sheer destructive presence, wading through enemy lines with crushing claws that tear apart fortifications and vehicles alike. The Ork mind inside remains every bit as aggressive as it was in its original body, and Deff Dreads are known to occasionally ignore orders entirely in favor of charging toward whatever target looks most satisfying to demolish, a habit mekboyz have never quite managed to engineer out of the design.