Lava Release (溶遁; 熔遁, Yōton, English TV: "Corrosion Style" or "Lava Style") is a combined nature transformationkekkei genkai made up of techniques that mix fire and earth-based chakra to create volcanic materials such as lava or rubber in different properties and usages.
Mei Terumī of Kirigakure utilises a Lava Release unique to her that takes the form of a strong acidic mud which can both be used offensively and defensively. Initially in the anime, her Lava Release took the form of molten rock in liquid state.
There is a subtle difference in the meaning of the kanji used for this kekkei genkai. Although both mean "to melt", the kanji with the "fire" (火) radical (熔) is outdated and means "melting with fire", whereas nowadays the kanji with the "water" (水) radical (溶) is normally used. Mei Terumī's Lava Release: Melting Apparition Technique, which utilises a strong acidic fluid, is the only Lava Release technique written with 溶. This, along with the fourth databook stating that Mei's Lava Release kekkei genkai can only be used by her, indicates a difference between 溶遁 and 熔遁.
In the third databook, the "water" kanji is used in Rōshi's article, whereas in the glossary, the "fire" kanji is used. In the fourth databook, only the "fire" kanji is used for Rōshi's Lava Release.
This kekkei genkai element shows the most different users with no known blood connection to each other, from most varied villages.