Hotaru is the only child of former Pro-Hero Hawks, born after his retirement following the loss of his wings. Unlike his birth father Hotaru is very quiet and doesn't enjoy interacting with others, as he struggles with social conventions due to autism. His childhood was rather sheltered, which suited Hotaru's personality. Things changed drastically when his quirk developed at age five - despite having the same mutation as his father Keigo granting him wings, his quirk was pyrokinetic. Because of the trauma Keigo experienced due to fire, he was unable to handle Hotaru's quirk. In desperation he sought out Endeavor, who unbeknownst to Hotaru was his other father. The family moved in to the Todoroki estate where Hotaru could hone his flame quirk under the tutelage of Endeavor. Hotaru was eventually accepted into UA where he is part of class 1-B.
FlightHotaru is able to fly with the large red wings he inherited from his father. He is not able to fly as fast as his father could as a pro, as he does not have the same control over his feathers.
PyrokinesisHotaru's quirk allows him to create and control fire. He can manifest it from any part of his body, including his feathers even after they are detached. When used in conjuncture with his wings he can create a powered boost, however he cannot sustain it long.
Takami Keigo | Father
Keigo raised Hotaru by himself for the majority of his young life before they moved in to the Todoroki estate. Being extroverted as he was, his father didn't understand Hotaru's nature growing up and often tried to push him "out of his shell". After Hotaru's diagnosis he learned to rein himself in regarding his son and their relationship became more stable. Despite their vastly different personalities, they care very much for each other.
Todoroki Enji | Father
Hotaru saw how much of a fan his father was of Endeavor and grew up idolizing him as a result. Once Hotaru's quirk developed, he began training under Endeavor, much to his delight. Though he doesn't know the nature of Endeavor's relationship to him, Hotaru gets along extremely well with Enji. He is a calm rock in his life and he would find himself seeking advice from him when he didn't feel comfortable asking Keigo.