Thunderstorm, a Komanian from Komania, is one of Ben's original forms in Ben 10 OMEGA
Ben first transformed into Thunderstorm when fighting Albedo on Komania, Thunderstorm's home world, when he decided to blend in after recognizing an alien in the Ultimatrix as resembling the natives. Thunderstorm quickly became one of Ben's favorite forms, and was used often in battle and to mess with Gwen and Kevin. After the Ultimatrix was recalibrated and the Master Control removed, Ben kept control of Thunderstorm, though he used him less often with the advent of Fourarms and Humongousaur.
Thunderstorm, while he may look imposing, isn't physically powerful. Instead, he has great mental powers that helped give him the edge in battle. Each of his four arms had a symbol that indicated what the arm could do. The symbols were as follows:
Rain cloud = Water
Snowflake = Ice
Gust of Wind = Wind
Brain = Minds
In addition, the soft substance of his skin meant that he was incredibly hard to harm.
In his Ultimate form, Thunderstorm's skin becomes rubbery and orange, and he gains a full face. He also has six arms; the additional two (a sun and a moon) control light and darkness. In addition, Thunderstorm gains greater control over each element.