Where an ordinary Mekboy tinkers and repairs, a Big Mek dreams big. These are the largest and most accomplished engineers in greenskin society, Orks whose obsession with building bigger, louder, and more dangerous machines has earned them both the resources and the respect to indulge it. A Big Mek is as content swinging an oversized wrench in melee as he is bolting together some new contraption, and his warband tends to bristle with experimental gubbins that no sane species would trust to fire twice.
A Big Mek's signature creations are the stuff of Ork legend. Some carry a Kustom Force Field, a jury-rigged energy screen, frequently built around a looted and heavily modified alien shield generator, that throws a protective bubble over the Orks nearby. Others lug a Shokk Attack Gun, perhaps the most unhinged weapon the greenskins have ever devised, which tears a tunnel through the warp and fires screaming snotlings down it to erupt inside the enemy ranks in a frenzy of biting and clawing. Precisely where those snotlings come out is never entirely guaranteed.
For all the danger their inventions pose to friend and foe alike, Big Meks are indispensable. They keep the Waaagh!'s vehicles running, forge the mega armour that clads the richest Nobz, and coax life out of machinery through the peculiar Ork certainty that a device will work simply because its builder knows it should. To a Big Mek, every battle is really a field test, and every spectacular malfunction is just fresh data for the next, even bigger idea.