Disney+ show.
First introduced on Mandalore.
Bo-Katan was indeed the last known person to own the Darksaber, until Moff Gideon was seen with it on The Mandalorian. How exactly the villain got his hands on the weapon is anyone’s guess, but the renowned blade is certain to play a huge role in season 2, and indeed Gideon actor Esposito has indicated that he gets plenty of chances to use it in the season. Speaking to IMDB, Esposito revealed that he shot some fight scenes that are “really going to excite” fans and actually broke three Darksabers in the process. When asked how his lightsaber skills are coming along in general, Esposito said:
I’m decent. I’m getting better. But you have to respect the power of it, the energy of it. It’s long, dude. I’ve bopped myself three times already. Pop in the head, I’m like oh my God, what do I do? I start laughing. People look at me, they want me to be the expert right off the bat, because I’m the bad ass. But you know what? It takes practice. So we have long ones, we have short ones. Because sometimes they have to put it in. And guess what? I can say this? I can say it, I can say it. I’m going through it in my head, spoilers, blah blah blah. I can say it. I’ve broken three of those bad boys.
It’s really not a spoiler for Esposito to it he uses the Darksaber a lot in season 2, as it was always fair to assume the ancient weapon would be a central part of the storyline. Din Djarin aka Mando will certainly know the sword’s backstory and will be itching to take out Moff Gideon and restore the saber to its rightful place on Mandalore, which will no doubt lead to some epic battles (it's already been revealed that the season contains at least one awesome lightsaber duel).
Set to arrive in Fall 2020 (pending any schedule changes brought on by the Ahsoka Tano, who will be played by Rosario Dawson. After a hugely successful first season, the second chapter of The Mandalorian is without doubt one of the most highly anticipated shows on streaming or television and is quite frankly the most promising thing the Star Wars franchise has in the pipeline right now.
Source: IMDB