General Kozu

General Kozu was the leader of the Overlord's Stone Army, having acted as the supreme military commander when his master was occupied elsewhere. Kozu fought in the Stone Wars against the First Spinjitzu Master—a battle that ended with the Overlord incapacitated, while the Stone Army was sealed underground.

Years later, the Serpentine accidentally freed the Stone Army from their tomb shortly after they were awoken by the Great Devourer's venom. Kozu reunited with the Overlord and served under Lord Garmadon, who wore the Helmet of Shadows. Kozu fought the Ninja on the Dark Island and later in Ninjago City. There, Dareth seized the helmet and gained control of the Stone Army, forcing Kozu to turn against the Overlord. Kozu was destroyed in the blast following the Overlord's defeat.

A statue of Kozu was later placed in the Ninjago Museum of History. When Cole accidentally opened the Departed Realm using the Yin Blade, Kozu's spirit escaped and possessed the statue. Seeking vengeance, he attacked Dareth with help from several Stone Warriors. Dareth reclaimed the helmet and controlled the Stone Army once more, commanding them to beat up and destroy Kozu. As a result, his spirit was sent back to the Departed Realm.