The Canonical Conundrum
Here's where things get a little tricky. There are technically two versions of Broly: the original, non-canon Broly from the Z movies, and the revamped, canon Broly introduced in "Dragon Ball Super: Broly." This distinction is crucial because their backgrounds, and therefore our potential answers regarding a last name, are quite different.
The original Broly, the one who goes "Kakarot!" a lot, exists outside the main Dragon Ball storyline. His power level is off the charts, and his backstory is, well, a bit over-the-top. In this version, the absence of a last name seems to fit the general Saiyan naming convention (or lack thereof).
The "Dragon Ball Super" Broly, on the other hand, is integrated into the main Dragon Ball timeline. His character is more fleshed out, his motivations are more understandable, and his story is treated with more nuance. This opens the door, ever so slightly, to the possibility of a more complex background, even if a last name isnt explicitly mentioned.
Ultimately, neither version of Broly is ever given a last name within their respective stories. But the canonicity of the "Super" Broly allows more room for fans to theorize and imagine possibilities. So, let's explore that a little further!
2. Broly (Super)
While the movie "Dragon Ball Super: Broly" doesn't explicitly state Broly's last name, it provides a richer backstory that might allow for some educated guesses. We learn more about Paragus's past, his relationship with King Vegeta, and the circumstances surrounding Broly's exile to Vampa. However, there is no explicit mention of any clan or family name.
It's important to remember that Saiyans, even in the "Super" era, aren't necessarily bound by the same naming conventions as humans. Their society is primarily focused on strength and combat prowess, not genealogy or social standing. Family is relevant, but formal last names? Maybe not so much. Also, the destruction of Planet Vegeta surely messed with a lot of record-keeping.
That being said, we cant rule out the possibility of a lost or forgotten family name. Perhaps Brolys ancestors had a different way of identifying themselves. Maybe a clan name was abandoned long ago. These are all hypothetical, of course, but fun to think about!
In conclusion, while there's no official last name for Broly, the revamped canon version leaves a sliver of hope — a hint that there might be more to his story than we currently know. It's a detail left to the imagination, which, let's be honest, is half the fun of Dragon Ball!