While many Dragon Ball fans would consider Lord Beerus to be the first God of Destruction introduced in the series, that wouldn’t actually be accurate as Dragon Ball GT confirmed the existence of such deities long before the events of Dragon Ball Super–well, sort of.
Lord Beerus was introduced in Dragon Ball Super chapter 1 by Akira Toriyama and Toyotarou as an elder space god whose only purpose in the universe was to keep life in check by regularly (and randomly) destroying planets. While Beerus was supposed to remain impartial, his love of cuisine almost always dictated his actions when it came to destroying a planet or not. If a world had food he liked, Lord Beerus more than likely wouldn’t destroy it. However, if he ate something on a planet that repulsed him (or just wasn’t exactly perfect for whatever mood he was in), Beerus would blow up the entire world without a moment’s hesitation. Even though Lord Beerus put his own spin on it, this was the job of a Destroyer God, and Lord Beerus played the role to perfection (minus the fact that he would regularly abandon his duties for prolonged slumber). While the existence of Lord Beerus in Dragon Ball Super certainly painted a clearer picture of what a Destroyer God is and what their duties are, the idea of Gods of Destruction within the Dragon Ball universe was not introduced in Super.
In Dragon Ball GT season 1, episode 11 (written by Masashi Kubota, directed by Osamu Kasai, produced by Toei Animation), Pan has infiltrated the temple of a cult on a far-off alien world while searching for one of the Black Star Dragon Balls. Previously on Dragon Ball GT, Goku, Trunks, and Pan set out in a spaceship through the cosmos hunting down the Black Star Dragon Balls. However, while on their journey, the team was split up and Pan found herself alone in a strange and dangerous world. Luckily, Pan was also with the newly-sentient Dragon Radar named Gill who told her that the cult’s temple contained the Dragon Ball she was after. Unfortunately, the temple also contained something else–something far more sinister: the God of Destruction, Lord Luud.
Lord Luud was Dragon Ball’s First God of Destruction, Not Lord Beerus
The Luud Cult is an organization that worships Lord Luud–an entity that is only described as being an all-powerful “God of Destruction” as that exact description is said multiple times by a number of Lord Luud’s disciples. However, while Lord Luud carries the title of a God of Destruction, Dragon Ball GT later confirms that Luud isn’t a deity at all, but is actually a super powerful android known as a Mutant Machine. This reveal that Lord Luud was actually a highly advanced robot was shocking to not only members of the cult who committed their lives to this Destroyer God, but to fans as well who thought they were getting a deeper glimpse into the otherworldly aspect of the Dragon Ball mythos–though the fact that there was a legitimate following for a God of Destruction, fake or not, proves it wasn’t all for nothing.
While Lord Luud ended up being an imposter, the fact remains that the idea of Gods of Destruction was first brought up in Dragon Ball GT and wasn’t something unique to Super. Plus, this GT storyline created an entire religion around worshiping Gods of Destruction, meaning this belief system is an established theology within this universe. Not only that, but Lord Beerus’ later inclusion in Dragon Ball lore actually gives credibility to the fact that Dragon Ball GT did beat Dragon Ball Super to the punch as his existence confirms that the Luud Cult did have the right idea in worshiping Gods of Destruction since they really are out there–an idea that was first introduced with Lord Luud, not Lord Beerus.