Heatwave used to be a leader of the Rescue Bots back on Cybertron, he had a happy family till the war between Decepticons and Autobots started. Heatwave is the only one that survived the war, Optimus Prime, his own team, Megatron and every other decepticon and autobot were dead. 

Heatwave shows to be cold and serious but inside he's soft and wants to be apart of a family. He just hides his softness so he isn't made fun of..
He looks up to Kade more than anything. He loves him with his spark...