The newest Star Wars animated series is doing what many shows before it have failed to do: make the Inquisitors seem truly terrifying.
The Inquisitors were introduced in the Star Wars canon with the animated series Rebels. They are a group of dark side Force users (mostly fallen Jedi) under the direction of Darth Vader, sent to hunt down the remaining Jedi knights across the galaxy. Since then, thye have appeared in the Star Wars: Jedi games, the Obi-Wan Kenobi series, the Tales of the Jedi and Tales of the Empire show, the Ahsoka series, and the Darth Vader comic line, among a few others. They are always seen hunting down the Jedi, but they’re mostly shown losing, portrayed as a minor nuisance while being described as a major threat. But with Maul – Shadow Lord, we’re actually seeing them as that threat.
The Empire sends Marrok (the First Brother) and the Crow (the Eleventh Brother) to Janix to hunt Maul and the Jedi, Master Eeko-Dio Daki and his padawan, Devon Izara. Both Inquisitors look really cool, and both are very formidable opponents. But if they look familiar, that’s because we have seen both of them show up in Star Wars stories before.
Specifically, both of them have fought (and lost to) Ahsoka Tano.
The Eleventh Brother confronted Ahsoka in Tales of the Jedi

We’ll start with the Crow. He appeared in Tales of the Jedi, having been sent by the Empire to a remote farming community where a Jedi was reported. There he encountered former Jedi Ahsoka Tano, who had been living in anonymity and obscurity. She used the Force to save a civilian, which alerted the Inquisitor to her presence. He turned his attention on her, but she very quickly evaded his attack, stole his lightsaber, and killed him with it. She cut his head off, and as his helmet fell to the ground, it deflated.
It was a very quick confrontation, and Ahsoka was able to defeat him without even having a lightsaber of her own. She used the Crow’s eagerness to kill her and get the reward for it against him, catching him off balance and besting him.
A key piece of information we don’t know is when this confrontation happened. Dave Filoni has become notorious for not really telling fans much of anything, so we don’t know even the date this happened in (because it appears to contradict a story told in the Ahsoka novel, which placed it one year after the prequel trilogy). It’s before Ahsoka joined the rebellion, but obviously after the events of Shadow Lord, which takes place around one year after Revenge of the Sith.
The First Brother confronted Ahsoka in Ahsoka

Years later, Ahsoka Tano faced off against the other Inquisitor seen in Maul – Shadow Lord, as the First Brother – also known as Marrok – was allied with Morgan Elsbeth in the New Republic era, as seen in the live-action Ahsoka series. He first fought Ahsoka on Corellia, delaying her from being able to further investigate and catch a transport being taken away by Imperial remnants. Not long afterward, Marrok joined with Shin Hati to fight Ahsoka and her apprentice, Sabine Wren, on Seatos, where these remnants made final preparations to go find Grand Admiral Thrawn. Marrok first helped to lead a ship battle, but then engaged Tano in a lightsaber duel on the planet’s surface.
As they fought, Marrok resorted to one of his favorite moves – using the spinning feature on his double-bladed lightsaber. Ahsoka saw through this tactic and disarmed him, swiftly killing him. As Marrok fell to the ground, green mist left his body.
There has been a debate among fans ever since Ahsoka came out whether Marrok was really there or whether he had been re-animated by Nightsister magick. Given how prominent a role the Nightsisters play in the series, along with the fact that they have an undead army of stormtroopers, it seems quite likely that Marrok had formerly died, but been resuscitated by the Nightsisters at some point.
Whatever the case, both of these Inquisitors fought the former Jedi Ahsoka Tano, and both of them were very swiftly defeated by her – without posing much of a threat at all. In Maul – Shadow Lord, their reputations are redeemed and their prowess is evident.