Part 14: Boss Guide: The Flesh
The Flesh is the second boss fight in the Warrens, and its the closest thing this game has to a "Dark Link" style of fight. The boss has one HP bar that it shares across four body parts, all of which can also shift into a different form at random and can have redundant parts. In theory, everyone is viable for this fight because this boss is entirely RNG and you will be reacting for the most part rather than planning ahead and having a teamcomp that can guarantee victory.
The Flesh's four parts all have their own individual traits and possess one unique action that comprise the whole body's action economy.
The heart is the squishiest target of the Flesh, and one your melee members will be hoping appears in the front row. From any row, the Heart can use Sanguine Stroke, which can heal a fair bit to the main body. Now unlike most games where you focus the healer to prevent this, you cannot willingly and permanently remove the heart from the fight , which is unfortunate. However, the Heart is the only target that has 0% prot among this cadre, so if it appears in the first two ranks then your melee team can easily out-damage its heal. The Heart also has astronomically low status resists, so you can stun it easily if you have the initiative or target DoTs on it specifically and watch as it stacks onto its next form. Its effectively the Flesh's giant throbbing weak point in videogame-isms.
The Spine, in contrast to the heart, is the tankiest form of the Flesh, possessing both high prot at 70%+ and having a stun attack with Bone Zephyr to both damage your team and lock them down. The Spine is an enemy you don't want to attack if you can because of how futile it is. High PROT means your physical damage won't be going through, and due to the unique mechanics of the fight if he morphs then any -PROT debuffs are left on the rank rather than the form itself. His status resistances are not great however; he can certainly fight off a stun well, however he has low DoT resistances, so that is still a valid strategy. In all honesty though, Bone Zephyr is the lowest threat unless there's more than one on the field. Its biggest threat is the stun which gives the flesh other attack opportunities, but it doesn't do much damage on its own. One last amusing thing: Bone Zephyr can only be used in the first 3 ranks, so if one appears in the back then it cannot act.
The Butt is the first of two offensive forms of the Flesh, and I'm hard-pressed to say if this is the worst form or the other one is. The Butt's attack is Undulating Invasion, and exists to mess with your back-row party members. This attack hits for a fair amount of damage, but also puts on a blight proc to further keep the damage rolling. Undulating Invasion also holds a high crit rate so you'll be seeing a lot of crits from it. Oddly enough, while the other body parts resist bleed more than blight, the Butt is the opposite in that regard so if its possible you want to blight other targets. The Butt has 30% PROT so its fairly tanky but is a preferable target compared to the Head and Spine. Stuns are somewhat viable and recommended on my part since I like my back-row buddies and don't want them butt-touched. There is one flaw to this form however, in that (apparently) he can only operate in ranks 3 and 4 and will pass if he somehow winds up in the front row.
The Head is the other offensive form, and probably the more dangerous form on average. Its attack is Maws of Life and it does a gross amount of damage accompanied by a bleed proc. It comes with 50% PROT so your front line offensive units will have a hard time cracking this nut. Much like the other forms, it posses less than average status resists so your stuns and DoTs are well worth it here. His moves can only be used from the first two ranks, however Maws also has the unique trait of having an off chance to attack two people at once. The Head is pretty beastly, and something you hope not to see more than one of.
For the Flesh, really any teamcomp can work since you'll mainly be reacting to its shifting forms rather than using a uniform strategy, however there are several tricks you can do. The first thing to note is that this boss is marked as Eldritch, not Beast so an Occultist with his knife and nukes can do a fair bit of damage here. You want your front line relatively strong so they can take a hit from Maws of Life and shake it off. This boss was designed to accent the DoT vs Prot mindset, so make use of that; Houndmasters with Hound's Harry and Plague Doctors with both Plague Grenade and Noxious Blast will do wonders here bringing unaltered consistent damage. On the note of Plague Doctor, their Battlefield Medicine can stymie a lot of the status effects the Flesh can bring to a fight. A hellion is a personal favorite of mine since she can hit the heart from anywhere. Arbalest has that same position versatility, though they trade being able to hit rank 1 for having a psychotic amount of crit. Abominations have their chain to stun any threats and go beast-mode when necessary. There's really a lot of things you can do with how random this boss can be.