Elden Ring: Commander O'Neil (Swamp of Aeonia) Boss Fight

As you probably know, bosses in Elden Ring are divided into three tiers. From lowest to highest: Field Bosses, Greater Enemy Bosses and finally Demigods and Legends.

Commander O’Neil is in the middle tier, Greater Enemy Bosses, and is found outdoors in the Swamp of Aeonia part of Caelid. Like most lesser bosses in the game, this one is optional in the sense that you do not need to kill it in order to advance the main story, but he drops an item that is needed to save Millicent from Scarlet Rot in the questline that is started by Gowry.

By the time you find this boss, you will probably have suffered multiple infections of Scarlet Rot from both the swamp itself and its inhabitants. Just in case you didn’t know, Torrent is apparently completely immune to Scarlet Rot, so if you ride him rather than run across the swamp, you will not get rot build-up from the swamp itself. If you get attacked by enemies that cause rot build-up, you will still get that though. I usually run everywhere as I really don’t like mounted combat and I feel exploration is more exciting on foot, so it took me a while before I noticed that the swamp is much more easily traversed on horseback.

Anyway, the boss itself is a large humanoid and when you spot him in the middle of a clearing you will know that he’s the boss around here, he just has that air to him. As soon as you start the fight, he will summon multiple spirits to help him. In order to avoid headless chicken mode overload, I decided to finally forgive Banished Knight Engvall for his previous shortcomings where he died and let me face a boss alone and accept him back into my service. This boss and its summons become a lot more manageable with a Spirit Ash there to take some of the heat off oneself.

In addition to summoning spirits, the boss has multiple area of effect attacks and also quite long reach with his weapon, so watch out for that. Other than that, Engvall tanked him very well, so it didn’t feel like a horribly difficult encounter. I would probably have been a lot more pressed if Engvall was still on suspension, but the advantage of being his boss is that I get to decide when that ends and that usually is very conveniently coinciding with my own tender flesh being in danger of a violent beating.

I decided to kill off the spirits before focusing on the boss. As you will notice near the end of the video, the boss does summon them again, but they will die when he does. I’m not sure if it would have been better to just focus him down first, but I find it usually works best in encounters with multiple opponents to kill the weakest off fast and make the fight simpler that way ;-)