The First Mate was among Soto's crew of pirates that sailed the Destiny's Bounty among the seas of Ninjago, two hundred years prior to the age of the ninja. At some point, the crew took down the Misfortune's Keep, a feared pirate ship under the command of Nadakhan.
When Captain Soto's pirates set sail in search of the Island of Darkness, the First Mate partied with several other pirates on the main deck, allowing No-Eyed Pete to steer the Destiny's Bounty. As a result, they quickly ended up steering the ship back to Ninjago and crashing into its rocky coasts, where the First Mate perished along with the rest of the crew.
The First Mate was revived when Lord Garmadon inadvertently used the Mega Weapon to restore Soto and his crew. The pirates quickly discovered the Serpentine aboard their ship and after arguing with them over whose ship it was, Captian Soto ordered them to be locked up in the brig.
With their prisoners secured, Soto and the First Mate ventured to the bridge, only to find it equipped with advanced technologies, including rocket boosters, allowing it to fly. Excited by this, the pirates flew towards Ninjago, eager to resume their reign of pillaging. They soon came across Ninjago City and began attacking it, though were eventually confronted by the ninja. After a brief fight, the pirates were subdued and taken into custody by the police.
The First Mate would later escape jail alongside Soto and No-Eyed Pete and would participate in the annual Ninjaball Run race. While traversing across the Sea of Sand, the First Mate manned the cannons on top of the pirates' vehicle and attempted to shoot the Darkley Students' bus but failed, causing the vehicle to crash into the edge of Crashcourse Canyon, disqualifying him alongside the rest of his team of pirates.