Skyhawks characters

Kai

Kai is Ace's late older brother. He is seen with dark brown hair and dark blue eyes. He has a striking resemblance to a Ace when he was a Storm Hawk. He was the Sky Knight of The Ultra Skuas before his death.

Kai was born to Sparrow Strike and Ida Storm. He loved his mom and siblings dearly and often had fights with his father on the abuse of Ace. After his mother dies, Kai gets his father arrested and fosters his younger siblings with the help of his team. About a few years later, Kai and Ace are on Terra Hallows on a field trip. Suddenly, a flash flood starts and nearly washes the two away but Kai manages to save his brother. However, he is unable to save himself from a large wave, which knocks him into the flood. He presumably drowns, as Ace is seen leaving the Terra without his brother. Kai is first seen when Kaida has a vision of the oracle disguised as a vixen named Mirage, who tells her of her father's past. It's later revealed Shadow Stalk was close acquaintances with Kai, claiming he was one of few Atmosians who wanted peace with the Exos. 

Kai had a strong bond with his younger siblings, especially his brother, Ace, even sacrificing his own life to save him. Ace misses him dearly.

Kai loved his mother and was devastated when she died.

He hated his father for abusing his younger brother.

Kai didn't have much to do with Lightning Strike.

Trivia:

Kai's name means fire. It also means water, a possible reference to his demise.

A theory suggests Kai survived his encounter with the flood and is now looking for his brother.

It's not known if Kai had any children.

Ace is implied to have PTSD, regarding Kai's death:

1. When asked if the teams have been to Terra Hallows, Ace and Piper both shout no. He subtly explains he had an unfortunate experience at the Terra. 

2. He is also shown to have a fear of fast moving water, having flashbacks of Kai's death.