It is difficult to say definitively who in the Touhou universe could beat someone in Undertale, as the power levels and abilities of characters in both series can vary greatly. However, some of the more powerful characters in the Touhou series, such as Yukari Yakumo or Reimu Hakurei, may have the strength and abilities to potentially defeat a character from Undertale. Ultimately, the outcome of a battle between characters from these two series would depend on various factors such as strategy, tactics, and the specific abilities of each character.
