Mortal Kombat 2021 is bookended by the appearance of Scorpion, one of the most popular characters in the games and a lethal fighter with a real sting in his tail. Once a mortal ninja called Hanzo Hasashi, Scorpion's powers weren't fully realized until he was killed by Bi-Han a.k.a. Sub-Zero and returned centuries later as a fire-wielding spectre straight from the depths of Hell.
It's revealed in Mortal Kombat 2021 that protagonist Cole Young is actually the descendant of Hanzo Hasashi. After becoming entangled in the upcoming tournament between the champions of Outworld and the champions of Earthrealm, Cole begins experiencing visions of his ancestor. In the final showdown against Sub-Zero, Cole uses Hanzo Hasashi's kunai - a knife that he attached to a rope to use in his final battle as a mortal - and summons the undead warrior now known as Scorpion to the fight arena. It's here that Scorpion is able to show off the full, hellish range of his new powers, culminating in a classic Fatality from the games.
Upon his return, Scorpion tells Sub-Zero that he has been residing in Hell - which, in the Mortal Kombat universe, is known as Netherrealm. While there are other characters whose powers are based around wielding fire, like Liu Kang, Scorpion's abilities are distinct because he has mastery over Hellfire, the all-consuming flames of Netherrealm. In the video games Scorpion's best-known Fatality is "Toasty!" - a move that involves him ripping off his mask and hood to reveal a Ghost Rider-esque flaming skull underneath, before breathing Hellfire that engulfs and incinerates his opponent. His Hellfire-based abilities make him a natural mirror for Sub-Zero's icy attacks, with their contrasting powers reflecting the centuries-old feud between them.
Outside of his ability to summon Hellfire, Scorpion is also deadly with his chain-mounted kunai, which he can use as a deadly whip to impale his enemies and drag them towards him with his signature cry of "Get over here!" As revealed in the opening sequence of Mortal Kombat 2021, Hanzo Hasashi's original kunai was one that his wife had been using to dig in the garden, which was then hastily tied to a nearby length of rope. In the ensuing fight, Bi-Han turned the blade onto Hanzo and killed him with it, and it subsequently took on supernatural properties that allowed Cole to use it as a summoning device.
The chain-mounted kunai can be used in combination with Scorpion's Hellfire powers, and is also where he gets his name from, since it acts as a "stinger" with which to lash out at his opponents. In one Fatality from the Mortal Kombat games, Scorpion actually transforms into a giant scorpion to finish off the other fighter. Perhaps he can show off that power in Mortal Kombat 2.