The line comes from Bleach, the long running anime adaptation of the manga series, where confident fighters regularly rank themselves against each other in battle. A short, self contained declaration like this was easy to lift from its scene and reuse out of context, so it spread through soundboards, anime edits and gaming clips as a ready made brag. It stays popular because the meaning is instantly clear even without knowing the original scene, and the calm arrogance works for both genuine wins and ironic, over the top flexes.