Dragon Ball Z villains can largely be separated into one of two categories: the primary ones, namely Frieza, Cell and Majin Buu; and setup ones such as Raditz, Babidi, the Ginyu Force and Dr. Gero. That said, there are also a few who came and went so quickly -- either for comic relief or convenient plot points -- that viewers didn't really get the chance to know their stories. One in particular stands out from the rest: Frieza's father, King Cold.
As the father of the most iconic villain in the series, King Cold's status as a galactic tyrant, character design and relation to Frieza immediately generated excitement for his appearance. Ultimately, he gets to Earth and lives just long enough to exit his spacecraft, see his son murdered by Super Saiyan Trunks, then beg for mercy before being killed off himself. It's quite the unceremonious ending for a supposed King of the universe. However, this then makes one wonder why, if a character of such power and magnitude was sitting there in the DBZ universe all that time, he wasn't given a larger role, or even a short story arc of his own?
Dragon Ball Super: Broly provides a relatively simple answer to this question. In a flashback scene, it's revealed King Cold announced his retirement and left the Saiyans -- along with the rest of the universe -- in the hands of his even more sadistic and racist son, Frieza. In other words, Cold spent his later years living a life of leisure until he heard about his son's loss to Goku. It's a fitting explanation considering his elegant, yet arrogant, attitude and his generally calmer demeanor as compared to Frieza.
King Cold's later appearances in the Dragon Ball series were brief as well. In Hell, Pikkon defeats him with one blow, and King Cold is later seen among the group of villains cheering on Kid Buu in his fight against Goku and Vegeta. In Dragon Ball GT, he escapes from Hell along with many other classic villains during the Super Android 17 saga, but his fate is never shown. Instead, it's just assumed he was defeated and sent back to Hell with all the rest.
Despite his sad to the point of comical demise(s), some intriguing questions remain around the character. For example, in the film Cooler's Revenge it's revealed King Cold treated his older son Cooler badly while spoiling Frieza rotten. Why were the two treated differently? Why did he hand his title and responsibilities to Frieza rather than Cooler, who was stronger, more intelligent, and less prone to overconfidence?
Cold's base appearance is almost identical to Frieza's second form. Does he also have ways to increase his power, or is he not a shapeshifter like his sons? Dragon Ball Z: Resurrection F reveals Cold only ever feared two beings in the universe: Lord Beerus and Majin Buu. He even actually warned Frieza never to fight them. How exactly did he come to know about those two, particularly Buu, who had been sealed away on Earth for such a long time?
For such an underused and barely seen character, King Cold possesses plenty of interesting backstory and mysteries that could be unraveled further down the line. He'll almost certainly never have a revitalized character arc like Frieza has had in Dragon Ball Super, but just maybe we'll get more flashbacks and answers to the questions surrounding King Cold as the franchise continues.