Trickery? Ha! The fruits of my research are no mere trick!
~ Plague Knight
Plague Knight is a major antagonist in the indie videogame Shovel Knight, as well as the main protagonist of the DLC Shovel Knight: Plague of Shadows. He works for the Enchantress as one of the eight members of the Order of No Quarter. He is encountered by Shovel Knight at the end of the Explodatorium.
When the Enchantress was starting her reign of terror, she created a small team of eight knights known as the Order of No Quarter, with Plague Knight being one of them. Shovel Knight had to venture toward various areas to stop the Order. While Shovel Knight was venturing towards the end of the Explodatorium, he eventually came across Plague Knight. Both Shovel Knight and Plague Knight fought each other, and Plague Knight ended up losing to Shovel Knight.
Later on, while Shovel Knight was venturing in the Tower of Fate, he eventually came across Plague Knight, as well as the other members of the Order of No Quarter he defeated. Shovel Knight had to endure a Boss-Rush with all of the knights, including Plague Knight. In the end, Shovel Knight managed to defeat all eight knights, including Plague Knight. After Shovel Knight managed to defeat all eight members of The Order of No Quarter, Plague Knight and the other members are hanging on the edge of the tower for dear life. Shovel Knight can choose whether to save them or leave them to die.
Regardless of what Shovel Knight chooses to do, they are all shown in the epilogue during the credits, with some of them reforming and others paying for their actions. After Shovel Knight and Shield Knight defeated The Enchantress, Plague Knight then returned to the Explodatorium. There, he became a teacher for advance potions.
In the Plague of Shadows campaign, it is shown that Plague Knight has his own agenda, as he joined the order only to approach the other knights and capture their essences, which he planned to use to make the ultimate potion to impress his lover Mona. Dark Knight learns of his plans and attempts to convince him to stop, bringing Mona with him to the Tower of Fate. However, Plague Knight had already captured the Enchantress's essence, which made the potion unstable, so he is forced to fight a large monster which comes out of it. Upon defeating the monster, the potion stabilizes, but after being told by Mona that she already loves him, they decide to use it to blow up the Tower of Fate instead, which causes the citizens of the Valley to regard them as heroes, accept them, and allow them and their minions to come into town whenever they like.
Super Smash Bros.
Plague Knight appears in Super Smash Bros. Ultimate as a novice-level support spirit, which grants increased power to fire/explosive attacks. He can be obtained by scanning the Plague Knight amiibo or by defeating him in a spirit battle, which is against Doctor Mario on the Unova Pokémon League stage with increased fire and explosion power who is easily distracted by spawning Bob-ombs that are pulled towards him.