Dark Souls III: The Ringed City Review (KOMO)
A beautiful DLC to end the series, amazing boss fights, and the best covenant of the game. This DLC adds so much to the game that I understand the many negative comments on the Ashes of Ariandel DLC, because AoA is considerably short compared to Ringed City DLC. There are two areas, one of them is a disgusting swamp (Thanks, Miyazaki) the other one is a pretty city. PvEwise, it's challenging and fun. One of the bosses is the HARDEST boss Darkeater Midir in Dark Souls III in my opinion, while the other one being the most epic with the fight and its OST Slave Knight Gael . Oh, and my favourite part of the DLC that it has a covenant that I really like. It is an invasion covenant that makes you the BOSS for other people playing the game.
Long story short; if you're going to buy only one DLC, buy this one. But I still suggest you buy the season pass to get them both.