Volkert Haas proposed that Tašmišu's name was derived from the Hurrian word tašmi, which he translates as strong.
[2] In myths, his position appears to be that of a subordinate of his brother Teshub, and in one passage from the Song of Ullikummi he outright addresses him as "my lord.
"[3] He served as his sukkal (attendant deity), though as noted by Daniel Schwemer this role in ritual texts could also be attributed to the god Tenu.
[15] Worship of him is best attested from the Hurrian kingdom of Kizzuwatna, where he appears in various festivals related to Teshub of Šapinuwa.
[18] In the Song of Ullikummi, Tašmišu joins his siblings Teshub and Šauška when they go to see eponymous stone giant after being warned by the sun god Šimige.
[20] He also suggests to his brother that to find a way to defeat the new adversary they need to meet with the god Ea in his dwelling, Abzu, in the Hurrian myth assumed to be a city rather than a body of water.