DELTARUNE - THE ROARING FUTA

The Roaring Knight, or just the Knight (often referred to in all caps), appears to be the main antagonist of Deltarune as the newer Chapters come out. In Chapter 3, the Knight is the "final" and "secret" boss who, if "defeated,” drops both the Black Shard and a Shadow Crystal. According to its followers, the Knight boasts tremendous power, presumably the same power the Shadow Crystals hold. It reveals itself at the end of Chapter 3 after attempting to murder Tenna and begins a fight meant to end in a scripted loss.

No prerequisites are required to encounter and "defeat" them, but it is recommended to equip the Shadow Mantle as it greatly reduces damage taken, and allows the battle to be reattempted.

While the Knight's appearance seems amorphous in nature, their "resting" form possesses long limbs, pointed legs, jagged shoulder protrusions, and what appear to be holes in their hands. When first encountered, they are slumped over, "leaking" something from their helmet, and have a single, circular eye hole. When screaming, they have a monstrous, deer-like head and an open rib cage, featuring an eye in the center. When fleeing and kidnapping Undyne, they assume a large antlered bird-like form. They also often transform into a spinning ball when quickly moving between locations.

The Knight has yet to speak, but it is demonstrated that they have a desire to bring about the Roaring; when TALKing to the Knight with Ralsei during their fight, Ralsei pleads that they stop trying to invoke the Roaring. The Knight doesn't seem to be above deception, as they presumably misled King and Queen into believing that creating more Dark Worlds would simply spread the Dark World and potentially create a paradise, rather than bring about an apocalyptic event. They also laugh in a sadistic, mocking manner when taunted by Susie with a threat that holds no weight against their overwhelming power, knowing full well they can just open another Dark Fountain.

In the light world [around people they like, like you] they immediately turn almost... cute? whatever. in reality, the knight is dess holiday [daughter of the mayor carol and sister to noelle] and to summarize her: dess [before she was corrupted] was just punk rock-y and kind of emo? but outgoing. after some grand accident, she was turned into the knight. you were close to her, so you and carol and a few officials from hometown [the town this all takes place in] to take up a plan to make her normal again. your role in this? playing the hero, closing the fountains she made, and distracting the other 2 heroes [susie and ralsei]

Dess had a crush on your older brother asriel, but he went away for collage. so now her eyes are on you.