Scarlet Rot is one of the new status effects introduced in Elden Ring. In essence, it acts as a more notorious version of poison, quickly dealing multiple ticks of damage based on the target’s maximum health.

Lore wise, Caelid is steeped in the hazardous substance after shardbearers Melania lost control of the rot inside her during her duel with General Radahn. This disease drove him mad, while permanently scaring the region in the aftermath.

Even so, Starscourge Radahn is still an insanely hard boss. It certainly is one of the most challenging bosses FromSoftware has created. Fittingly, he is still vulnerable against Scarlet Rot, and players have been using this to gain an advantage.

But as players surely know, that isn’t enough to beat him. Unfortunately, there’s only so much Scarlet Rot Grease in the game. So players have to resort to crafting to keep that edge.

It doesn’t help that the main component, Aeonian Butterfly, is a tricky item to get. This guide will show you where to farm Aeonian Butterfly in Elden Ring.

Aeonian Butterfly Location

A quick disclaimer: if you’re on your first playthrough for Elden Ring, and you’re reading this guide to help you against Starscourge Radahn, I’m afraid this won’t help you.

The Nomadic Cookbook [22], which is used to craft Rot Grease, Drawstring Rot Grease, and Rot Pots, is found at a late-game area that you can access after defeating Radahn. I recommend using his secondary weakness, Bleed, against him. In general, Bleed is very strong in Elden Ring.

But this is still a useful guide on a new game plus playthrough, or if you’re a higher level character hoping to help your friend with the boss.

Butterfly

The Aeonian Butterfly is a rare crafting material mainly used to create Scarlet Rot-based items. The description reads, “A butterfly with withered, scarlet wings found in the swamp of Aeonia. According to myth, these butterflies were once the wings of the Goddess of Rot herself.”

You’ll mostly find the Aeonian Butterfly at Scarlet Rot-blighted areas of the map. Mostly in Caelid and the Lake of Rot.

They appear as floating entities in the world. When you see a group of butterflies, you can interact with it to collect one.

The Swamp of Aeonia is a great place to farm Aeonian Butterfly. Mount your horse and start circling the lake; you can collect a good number of it from here. 

Butterfly entity

Additionally, check out the decaying trees nearby that look like white honeycombs. You’ll usually find an Aeonian Butterfly there too. While you’re in the area, the merchant north of the Aeonian Swamp Shore Site of Grace sells Aeonian Butterfly. It has a limited stock though so buy it all up now.

Check out the nearby Sellia, Town of Sorcery landmark to farm Aeonian Butterfly. It’s usually near the trees.

The Abandoned Cave east of the Smoldering Wall Site of Grace has a bunch of them too. The reward for beating the area’s boss is significant since it drops the Golden Scarab talisman, which increases runes obtained from defeating foes.

The Lake of Rot also contains a fair share of Aeonian Butterflies; however, that place is like Blighttown on steroids. Make sure to bring many Preserving Boluses to stave away the affliction. If you have points invested into Faith, use the “Flame, Cleanse Me” incantations to rid yourself of Scarlet Rot build-up.

Assuming you did laps around the areas and gathered every Aeonian Butterfly, you may notice that resting at a Site of Grace doesn’t respawn them, unlike the Smoldering Butterfly, for example. To my knowledge, they don’t respawn, or they may take a very long time before they do.

I checked back every hour or so to no avail. I fast-traveled to reload the area repeatedly and even quit the game. It seems that the Aeonian Butterfly doesn’t respawn.

Therefore, if you need to farm Aeonian Butterfly, you can loot it off enemies. But I’m warning you now it’s an arduous grind because the drop rates are so low.

First, the Aeonian Soldiers drop the Aeonian Butterfly. These are shriveled enemies who look like prawns patrolling the area. I fought them ad nauseam that I ended up amassing an impressive collection of their weapons, but with a pathetic stock of Aeonian Butterfly.

Aeonian Soldier

My farming spot starts from the Smoldering Wall Site of Grace, then following the main road south to kill the two soldiers. Afterward, I go back, reset, and repeat. Even while relentless chugging down the Silver-Pickled Fowl Foot, an item that increases item discovery, chances were still abysmally low.

The Basilisks in the Lake of Rot have a much better chance of dropping the item so that you can farm Aeonian Butterfly from them. But as previously mentioned, you’ll have to fight them on the Scarlet Rot-blighted lake itself, so it’s a huge hassle.

So far, this is how I farm Aeonian Butterfly in Elden Ring. Perhaps FromSoftware made it difficult to farm because Scarlet Rot is a powerful status effect. 

Personally, it’s a time-consuming grind, and you’re better off using Rotten weapons to inflict the status effect. I heavily recommend finding dragon hearts then purchasing the Ezykes’s Decay dragon incantation. I’ve been having a blast utilizing that spell both in PvE and PvP.