How to Beat the Congregator of Flesh
Details
Location: Forsaken Fen
Resists: Wither, Holy, Smite, Poison
Weakness: Fire
Summons: None
Rewards
Remembrance of the Congregator of Flesh
10 Umbral Scourings
1 Vestige Seed
How to Beat
The Congregator of Flesh has a lot of health for the point of the game that you meet him. You likely don't have many items to choose from, and you likely don't have them upgraded much, so you are relying on tactics.
And our tactic here is simple - play aggressively. It may seem like the way to win this fight is to play conservatively, but the Congregator of Flesh hits hard and has several ways of punishing you. Due to his size, it can be difficult to see what moves are coming if you are in close quarters.
So, to reduce the capacity for error, we are going to be dealing with the Congregator of Flesh as quickly as possible. You will notice that you can lock on either to his main body or his leg - that leg is the way to go.
Get close, lock onto that leg, and keep strafing around the Congregator of Flesh to your left. As often as possible, perform fully charged heavy attacks on that leg, and in time, you will break the boss's posture, leaving him open to a critical strike.
When you are doing this, there won't be as many moves to watch out for. The Congregator of Flesh will almost never use his overhead slams or his roar, and will only occasionally use his backhand swipe as he turns around, trying to get to you.
The main thing to watch out for, however, are his slams. The body slam and jumping slam will both be used in excess while you are working on this strategy, which is fine because they are surprisingly easy to avoid.
If you have access, it is recommended to dual wield weapons to maximise your damage output here.
Movepool
Overhead Slam: Up to three times, the Congregator of Flesh will raise its arm and, after a delay, slam it down in front. The wind-up is clear, but the attack comes out fast, so it is trickier to dodge than it initially seems. Do so by dodging to the side, not backwards or forwards.
Side Swipe: The Congregator of Flesh will pull his arm close around his front and then swipe outwards over a wide area. Dodge through the hit to avoid the damage.
Body Slam: If you are behind the Congregator of Flesh, he will rise up slightly before falling backwards, covering a fairly wide area and dealing high damage. This can be easily avoided by dodging the hit, even if it looks like you are still in the impact zone.
Jump Slam: The Congregator of Flesh will jump a few feet off the ground and slam down, dealing high damage. Similar to the body slam, this is easily dodged, even if it looks like you are still in the impact zone.
Roar: The Congregator of Flesh will let loose a roar which covers a relatively wide area around him. It deals no damage, but will knock you down, and is often followed up by another attack. The Congregator of Flesh will always start the fight with this.
Grab Attack: The Congregator of Flesh will shake his head before performing a swiping grab from the right to the left. He can turn while doing this to grab you at his side or behind him. He will then quite literally chew you up and spit you out. You must dodge backwards to avoid the grabbing hand.
Lunge Swipe: The Congregator of Flesh will lunge forwards will swiping from your right to your left, dealing high damage. Dodge forward through the attack and punish.
Poison Mist: After around 60% health, the Congregator of Flesh's jump attacks will create poison mist clouds around him. These will slowly build up your poison meter, and if this fills, the fight will become very difficult to survive. Avoid these as best you can.