King Charlatan is the main antagonist of "Baby, It's Cold Outside" - episodes 41-42 of the original My Little Pony series. Although starting off as a dark and evil tyrant with ambitions to rule the world (and even expressing genocidal thoughts) he would later redeem himself due to his love for his son.
When first introduced King Charlatan is quick to show himself as an antagonist, to the point of stating that he wished all non-penguin species to be eradicated as he used his magical stare to freeze the surrounding Ponyland, with aims of spreading his influence across the entire world.
Despite King Charlatan's seemingly evil mindset his young son was quick to try and reason with his father, alongside his friend (who was a duck and thought of as "weak" by King Charlatan). Sadly the attempts to reason failed and King Charlatan froze his son's friend in ice as a show of power.
Due to this his son would aid the ponies after they were captured by King Charlatan's guards and tried to help them stand up to him, only to be frozen himself. However after freezing his own son King Charlatan slowly begins to realize the errors of his ways (aided by a song entitled "How Can You Be So Cold?" sung by Megan and the ponies). After this he gives up on his previously cruel mindset in order to be a better father (and by extension a better ruler).