season 2 finale showed the upgraded soldiers in action — as it turns out, this class of Imperial fighter is shaping up to be a force to be reckoned with.
In "Chapter 16: The Rescue," Moff Gideon reveals that Dark Troopers aren't human at all, but are in fact a super-powered model of droid. When Din Djarin, Bo Katan, Fennec Shand, and Cara Dune are about to crash-land on his ship, Gideon orders his crew to activate an entire fleet of dormant Dark Troopers - which proved to be formidable adversaries for even Djarin. Even against one Dark Trooper, Djarin struggled, and his head frankly would've been crushed in if it weren't for his pure beskar helmet.
To activate the Dark Troopers, Gideon's crew needed to lock in a special key before releasing the droids from their holding pods. This hints that deploying these droids is notably more difficult than any other average model of droid. Since Gideon only calls for this order once Djarin, Kata, Shand, and Dune have actually boarded his ship, it seems that they're combat units that are only to be utilized in exceptional circumstances.
The Empire might want to use these droids sparingly specifically because they're such powerful units. Their armor is resistant to blaster shots, flamethrowers, and even whistling birds. Most of their bodies are impervious to beskar steel (suggesting that Dark Troopers are made of beskar themselves) except for an exposed part of their necks. Djarin manages to strike his staff through this weak spot against the Dark Trooper he's fighting, finally destroying the droid and putting an end to a fight that wasn't looking too promising for him just moments earlier. Unfortunately, the Dark Troopers Djarin shot out into space were able to fly back into the ship. No one is able to stop the remaining Dark Trooper platoon from punching and prying its way through ship doors to all the way to the bridge.
No one, that is, except for Luke Skywalker. Though the Dark Troopers are definitely formidable battle droids, they're not completely invincible. The season finale's climax reveals this key weakness in the Dark Troopers' design: they're completely helpless against a lightsaber. When Luke Skywalker (a de-aged Mark Hamill) boards Moff Gideon's ship, he effortlessly slices his way through the entire platoon of Dark Troopers. Luke's arrival is so devastating to Gideon that he tries to kill himself, which indicates that a Jedi might be the Dark Troopers' Achilles' heel.
Though Luke is able to swoop in and save the major players in The Mandalorian, he is still only one Jedi left from an Order that's been, for all intents and purposes, wiped out. Since Grogu is about to begin training with the very Jedi who brought about the Empire's downfall, perhaps viewers can look forward to the youngling playing a key role in defeating the Dark Troopers in the future.