Dr. Stone Wiki
Dr. Stone Wiki

Sulfurina (スルフリナ Surufurina), or Ryu-san (リューさん Ryū-san) in Japanese, is the name of the embodiment of the Emerald Green Spring, a hot spring that emits a deadly poisonous gas consisting of hydrogen sulfide and sulfur dioxide. The group has to tread to retrieve sulfuric acid from the spring to make sulfanilamide to cure Ruri of her illness. Silver can be used to detect hydrogen sulfide to see where the poison gas is and to avoid it.[1] She is also the personification of sulfuric acid itself who appears in roadmap diagrams whenever the acid is used.


She is not a real being, but her illusionary representation has her looking like a beautiful goddess in a long white dress, wavy, long emerald green hair with a flower crown on-top and big green eyes, white angel wings and wears thigh-high socks; however, she quickly turns into a gross, distorted melting face, and even a giant skeletal demoness when people get too close and die from her gas.


She is not a real being, but has the appearance of a beautiful benevolent goddess that lures people in but once they get too close to the poisonous gas she emits, she reveals her true colors as a vicious demoness ready to swallow and murder anyone who gets within her clutches.

Skills and Abilities[]

Her poisonous gas is capable of killing anyone who comes too close. The only chance of avoiding her gas while treading her territory is to wear a gas mask (made by Senku) though one must remain calm as hyperventilating and breathing too much and panicking will cause a quicker loss of breath than the gas mask's ability to purify the air.

Chapter Appearances[]



  • Senku nicknames her Ryu-san because in Japanese the word for sulfuric acid is "ryusan" (硫酸 (りゅうさん) ryūsan), which sounds like the name "Ryu-san". In the English translation he calls her Sal.


  1. 1.0 1.1 Dr. Stone Manga: Chapter 30

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