The twisted tinker Mekgineer Thermaplugg is the final boss of Gnomeregan. Mekgineer Sicco Thermaplugg was once a brilliant and wise tinker, who despite being incredibly frail even at a young age, was destined to be High Tinker. He cunningly laid the way to the seat, charming people to his side and cranking out one great invention after the next. He worked unceasingly toward his goal, for Thermaplugg planned not only making High Tinker, but also becoming the gnome's first true king in over four hundred years. He envisioned a great kingdom out of New Tinkertown, carved out of the entire western half of Dun Morogh, even if it meant relocating the nearby dwarven communities in the name of progress. Nothing would stop him! However, his closest friend, High Tinker Mekkatorque, ruined all of his goals when the council of tinkers decided that Thermaplugg was too ambitious and chose Mekkatorque instead.

This NPC can be found in Gnomeregan.