Where Did The 'Happy Birthday Daniel' Video Come From? Re:Zero TikTok Meme Explained

Happy Birthday Daniel refers to a meme wherein the character Subaru Natsuki from the anime and light novel series Re:Zero aggressively wishes a nebulous "Daniel" a happy birthday, saying: "Happy birthday Daniel! Did you really think I’d let this day pass quietly? I know the kind of power you vibe with, the kind that keeps climbing no matter what!" The meme, which began spreading on TikTok in 2026, appears to have originated from an unrelated trend where parents create AI-generated videos in which children's favorite characters wish them a happy birthday. The "Daniel" video's spread in particular is likely due to its association with the popular Aura Monster / Subaru Walking Up Stairs meme.