Curse is a sonic.exe OC created by Kenji Grimm (also known as KK) as a character for roleplays on twitter in 2021, with a "story" being written for him shortly after. Curse was created during an initial hype of saturated sonic.exe clones and OCs that was initiated from the Friday Night Funkin' mod "VS Sonic.exe".

Curse is Sonic who one day was cursed. Resulting in a boulder killing Knuckles and crippling Sonic, with the prople blaming him for Knuckles' death. The curse over time ends up tragically killing all of Sonics friends as Eggman ended up caring for Sonic until his death as well.

For more information, check here:
https://cult-of-xyclopedia.fandom.com/wiki/Curse