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.
About this sound
Sorry but I'm number one is a confident voice line from the Bleach anime, used as a sound effect for bragging, winning and flexing in edits.
This short clip captures a single smug voice line delivered with complete confidence, the speaker calmly declaring himself number one as if it were an obvious fact. The delivery is cool and dismissive rather than loud, which makes the arrogance feel even funnier and more cutting. There is no build up or extra dialogue, just the clean statement landing on its own. Played over a victory, a ranking or an unexpectedly good performance, it instantly turns an ordinary moment into a boastful punchline that needs no explanation for the audience watching.