The following contains a major spoiler for Solo: A Star Wars Story. If you don't know, you really don't want to know this before you see the movie.
Solo: A Star Wars Story contains a major character reveal that took the audience by surprise. It turns out, we have Ron Howard to thank for seeing him return. Apparently, the exact identity of the power behind Crimson Dawn hadn't actually been decided when Ron Howard came on board as the director for the film. However, there was a list of potential candidates to play the big boss and Howard pushed hard to use the one that eventually showed up on screen. Here come the spoilers. According to Howard...
It just sort of said 'Boss.' And I thought when I came in, I assumed they knew who it was and they were just keeping it under wraps. And they didn't. But Maul was listed as one of the candidates. And I lobbied hard for that. I thought that made a lot of sense to me. I found that character to be really effective. And I knew for a fact, without asking directly and giving anything away, my son Reed who just turned 31, who's a dedicated Star Wars fan, he's a golfer. He's not in the business. Dedicated Star Wars fan. I just whispered that possibility and he just thought that would be incredibly cool. And so for that generation, I thought, well that was gonna be a pretty interesting idea. And doing a little more research and understanding sort of how the character had worked elsewhere, I thought it was good. And the Kasdan's were on board with that. And but then we actually shot it twice. Because we did it once. And then we realized we, it wasn't quite Maul enough yet.
Apparently, Ron Howard reveals to Slashfilm, the original version of the scene didn't include the lightsaber. The duel bladed weapon is Darth Maul's signature, as he was the first in the Star Wars universe to wield such a device. In this case, the hilt is a bit different than the version Maul used originally, looking much more menacing, so the reshoot was probably a good idea.
The most fascinating thing about the fact that Ron Howard had a hand in deciding that Darth Maul would be the one Dryden Vos was answering to, is that it means that the no decision had been made during the entire first half of filming when the movie was being helmed by Phil Lord and Christopher Miller. It's true that the character doesn't have any direct influence on the film as a whole, so you don't need to know who the character will be until the time comes to film the scene, but it's certainly interesting that this piece of the movie had been left undecided.
While I'm curious who the other candidates were for the spot, Maul is a solid choice. The character has always been popular, even with him being so minimally used in Star Wars: The Phantom Menace and while fans of the Star Wars animated shows have seen him before, Solo allows Maul to become part of the big screen canon once again.