Kassian is Cyclonis's feline son. He has black fur and amber eyes. He wears a red and green outfit with a red scarf around his neck and fights using a crystal staff.

Kassian owns a ring called The Storm Ring, made out of a wind stone crystal. He uses this ring to control and manipulate storms. This was given to him by his mother on his 7th birthday, stating he was the chosen one of Tempest, the storm goddess and his job would be to protect the storms that surround Cyclonia and would use them to destroy the Atmos.

He has a very friendly nature and thinks things can be solved with peace and not war. However, he does inherit some of his mother's personality. He loves singing, music, and animals.

Unlike his siblings, Kassian believed Kieran was dead but never revealed this thought to his brothers or sisters. Kassian agrees to help Jason find his family and develops a close bond with him.

Trivia:

Kassian is named after his aunt, Kassie who also has a black cat-like form.

Kassian is the second male feline Exosian child to be introduced, the first being Skylar.

Though he, Rain, and Monsoon were given magical items that use either the sun, moon, or storms as their source of power, Kassian is the only one who is given the task of using his gift to destroy the Atmos.

Despite the storms around Cyclonia being lifted, Kassian's ring does not lose its power.