The Chorusling is the first Legendary Monsters mob you’ll meet in the End, and it stands about 2.5 blocks tall. It walks rather than charges, and it will come for you the moment you’re inside 14 blocks of it. The swing itself isn’t what hurts, it’s what the swing leaves on you.
Every hit that connects gives you Chorus Infection. You’ll run into Choruslings wandering the outer islands on their own, and in proper numbers inside the Ancient Tower Remains, where spawners keep feeding them at you alongside the Chorusent. They’re also the only source of 
Infected Chorus Fruit, so you’ll be killing plenty of them either way.
Spawning
Choruslings spawn naturally in three End biomes, and they spawn one at a time rather than as a group, so out in the open you’ll be handling singles. Like any monster they need the dark, and since the End has no sky light at all, that means any unlit 
End Stone is fair game. 
Torches around an outpost are enough to keep them out of it.
The Ancient Tower Remains is where you’ll actually meet them in bulk, and that only generates in End Highlands and End Midlands. Three Chorusling spawners sit inside it, each one waking up once you’re within 16 blocks and pushing out up to 4 at a time, every 10 to 40 seconds.
Each spawner stops once 6 are already standing nearby, then starts again as you thin them out. They’ll keep doing that for as long as the spawners are intact, and all three sit down at the base alongside the Chorusent, so there’s no clearing them on your way in and then fighting in peace.
If you’d rather not sail the End hunting for one, an 
Eye Of Chorus will point you at the nearest tower. It’s crafted from 4 
Chorus Fruit around an 
Ender Pearl, and the fruit grows all over the outer islands anyway.
Thrown like an 
Eye of Ender, it flies off in the right direction and usually drops back down for you to collect. If there’s no tower anywhere in range it simply won’t throw, so you don’t lose the Eye finding that out.
Behavior
A Chorusling is hostile on sight and will pick a player over anything else in range. It’ll also target 
Snow Golems, and it counts the Flameborn as enemies, so a Flameborn Guard, a Flameborn Warrior, a Wandering Eye or a Flame Drifter that strays into the same fight will get attacked as well. Outside of that it just walks at you and swings.
Attacks
There’s only the one attack, a heavy swing that reaches about 3.5 blocks and lands roughly once a second. Against a player that’s 5 damage on Normal and Hard, and 8 on Easy, so dropping the difficulty won’t soften it. The reach is what catches people out, as it’s longer than your own, so trading toe to toe means you’re taking one for free every exchange.
Any hit that gets through while you’re not blocking applies Chorus Infection for 3 seconds. It goes off a few times while it’s running, each time for 3 damage through armor plus a short hop to a spot with solid ground under it. That’s around 9 extra damage per dose, and while it won’t drop you into the void, it pulls you out of position mid-swing.
Raising a 
Shield stops the infection for that hit as well as the damage, but the Chorusling drops your arm and disables the Shield for 2 seconds afterward. A Shield is still worth carrying, you just can’t hold block your way through four of them coming out of a spawner.
Weaknesses and Immunities
Fall damage and standing in fire are both ignored, so a drop pit or a burning floor won’t soften one up. It isn’t fire immune in general though, so Fire Aspect burn still counts against it. That leaves melee, and melee is what the whole fight is built around.
Choruslings ignore anything fired as an 
Arrow completely, including regular Arrows, 
Spectral Arrows and thrown 
Tridents. A 
Crossbow loaded with 
Firework Rockets still works, since a rocket isn’t an Arrow, and Splash Potions land normally as well.
It sits on 70 health with 6 armor behind it, and half of your knockback gets resisted, so you won’t be shoving it back out of its own reach between swings. It isn’t Undead either, so Smite does nothing here and Sharpness is the enchantment that actually pays.
Chorusling and Chorusent
Inside the tower you’ll be dealing with both at once, and the Chorusent‘s ground attacks skip its own Choruslings, so there’s no lining them up and letting the boss do the work. They’re built very differently, which is worth a look before you decide what you’re killing first.
Chorusling
Chorusent
On paper the Chorusent is the bigger threat, but the Choruslings arrive in fours and keep coming while the spawners stand. Break those first and the boss fight is the easy half of the visit.
Drops
Every Chorusling drops Infected Chorus Fruit, and the count doesn’t scale with Looting, so there’s no reason to swap weapons before you clear a room. The drops never despawn, which is handy when you’d rather fight first and pick up afterward. They’re only worth 2 experience each though, so this isn’t somewhere to farm levels.
Chorusling Drops
Infected Chorus Fruit The fruit is the crafting material behind the whole Chorus line. 2 of them go into a 
Chorus Blade alongside an 
Iron Sword and a 
Chorus Crystal, the 
Chorus Cannon takes 2 more with a 
Sand Cannon, a Chorus Crystal and a 
Gold Ingot, and a single one goes into the 
Chorus Mask.
8 of them around an 
Entity Warper makes a 
Void Entity Warper instead. Keep a few spare as well, since the fruit is what repairs the Chorus Blade and the Chorus Cannon on an 
Anvil.
The Chorus Crystal that most of those need comes off the Chorusent rather than the small ones, so the Choruslings give you the bulk and the boss gives you the rare part. You can eat the fruit for 5 hunger, but it’s guaranteed to give you Chorus Infection for 8 seconds. That’s rarely a trade worth making unless you’ve already got the Mask on.
Tips
Make the Chorus Mask before you commit to a tower. It’s the mod’s own answer to Chorus Infection, and worn on your head it strips the effect off you as fast as the Choruslings can apply it, which turns the whole thing into an ordinary melee.
It takes 4 Chorus Fruit and one Infected Chorus Fruit around a Chorus Crystal, and that Crystal means a Chorusent has to die first. That can be at a tower you’ve already cleared, or the one you’re standing in if you’d rather craft it halfway through the visit.
A 
Milk Bucket will clear Chorus Infection too, and it’s the cheaper option if you’re only passing through the End rather than clearing a tower. It takes your other effects with it, so it’s a worse answer mid-fight than the Mask is, but it’s something to keep in a spare slot either way.
Leave the 
Bow behind and bring a sword. Arrows do nothing at all here, and since they come out of the spawners four at a time, a fast weapon that clears them quickly beats a slow one that wins the trade on paper. Their reach is longer than yours, so step in, swing and step back out rather than holding position.
Break the spawners before anything else in the tower. There’s no cap on how many they’ll produce in total, only on how many can be near you at once, so a drawn out fight with the Chorusent means a steady line arriving behind you. Two minutes spent on three spawners saves you far more than that later.
FAQ
They’re built to ignore Arrows outright, so the damage isn’t reduced, it simply doesn’t apply. That covers Arrows, Spectral Arrows and Tridents you’ve thrown, along with anything else fired the same way. Firework Rockets from a Crossbow still work though, as do Splash Potions, so ranged isn’t completely off the table.
It’s the base material for the mod’s End gear, going into the Chorus Blade, the Chorus Cannon and the Chorus Mask, as well as the Void Entity Warper. It also repairs the Chorus Blade and the Chorus Cannon on an Anvil. Most of those recipes want a Chorus Crystal too, which only the Chorusent drops.
The Chorus Mask handles it for you, as wearing it clears the effect continuously, so the infection never sticks. A Milk Bucket works too, it just takes every other effect off you at the same time. Blocking with a Shield stops the infection being applied in the first place, at the cost of the Shield going on cooldown for 2 seconds.
They spawn in the dark like any other monster, and the End has no sky light, so an unlit floor anywhere in End Highlands, End Midlands or Small End Islands can produce one. Lighting the place properly stops it, same as it would in the Overworld. They only ever spawn one at a time out in the world, so it’s a trickle rather than a flood.
