Commander O’Neil is the rot-soaked general waiting in the middle of the Swamp of Aeonia in Caelid. He swings a huge war banner, calls a squad of ghostly Exile soldiers to fight beside him, and the ground under your feet is Scarlet Rot the whole time. He is optional, but you need him if you want to finish Millicent’s questline, because he drops the Unalloyed Gold Needle. This guide covers where to find Commander O’Neil, what he is weak to, how to handle his summons, and what he drops.
Quick facts
| Boss location | Swamp of Aeonia, Caelid |
| Nearest Site of Grace | Inner Aeonia |
| Required? | No, but needed for Millicent’s questline |
| HP (NG) | 9,210 |
| Runes (NG) | 12,000 |
| Drops | Unalloyed Gold Needle, Commander’s Standard |
| Weak to | Pierce (0% negation) |
| Resists | Slash (35%) |
| Immune to | Scarlet Rot and Madness |
| Parry | Yes |
| Spirit Ashes | Allowed |
| NPC summon | Polyanna, Adopted Daughter (sign near Inner Aeonia) |
| Difficulty | ▰▰▰▰▰▱▱▱▱▱ 5/10 |
Where is Commander O’Neil?
- Travel to the Swamp of Aeonia, the red swamp in the middle of Caelid. Our how to get to Caelid guide covers the safest ways in.
- Find and rest at the Inner Aeonia Site of Grace. Look for the Polyanna summon sign nearby before you go in.
- Ride south from the grace into the large clearing ringed by twisted trees. The fight starts as soon as you get close.
The swamp water builds Scarlet Rot quickly, so carry a few Preserving Boluses and do not stand around in the rot between attacks.
What is Commander O’Neil weak to?
Pierce is his weak spot: it is the only damage type he has no negation against. Slash is his best-defended type at 35%, so a spear, rapier or thrusting sword hits noticeably harder than a katana here. Every element sits at 20%. He cannot be rotted and cannot be driven mad, but Hemorrhage, Frostbite, Poison and Sleep all work, starting at a buildup of 332.
| Damage type | Negation |
|---|---|
| Pierce | 0% (weakest) |
| Standard | 10% |
| Strike | 10% |
| Magic | 20% |
| Fire | 20% |
| Lightning | 20% |
| Holy | 20% |
| Slash | 35% (strongest) |
How to beat Commander O’Neil
- Bring help. Summon Polyanna from the sign near Inner Aeonia, or bring Spirit Ashes. A second target pulls him and his soldiers off you.
- Clear the first squad. He opens with five spectral Exile soldiers. Kill them early with wide swings or area attacks while he is still walking in, so they cannot stagger you later.
- Watch the banner. When he plants his standard and shouts, he buffs himself. Back off or use the moment to finish a soldier, then punish after his next combo.
- Get ready for the big soldiers. Later in the fight he calls three large Exile soldiers with greataxes. They hit hard, but once they die they do not come back, so deal with them before going all in on O’Neil.
- Use Torrent if you struggle. Riding keeps you out of the rot and lets you hit and run. He cannot jump, so mounted hit-and-run attacks are safe.
- Parry or break his stance. He can be parried, and breaking his stance with heavy or jump attacks opens a critical hit.
Best builds and tools
- Pierce weapons: spears, rapiers, thrusting swords or heavy thrusting swords.
- Bleed or Frost: both build up normally on him. A bleed build works well.
- Preserving Boluses for the rot, plus a talisman or armour with good Robustness if you plan to fight on foot.
- Skip Scarlet Rot weapons and Madness incantations: he is immune to both.
Rewards and the Unalloyed Gold Needle
- 12,000 Runes (NG).
- Commander’s Standard, the banner he fights with.
- Unalloyed Gold Needle, the key item for Millicent’s questline.
Sage Gowry needs the Unalloyed Gold Needle to hold back Millicent’s Scarlet Rot. Take it back to him to continue her story; our Millicent questline walkthrough covers every step and both endings.
Related: Caelid has several other tough fights nearby. See our guides to Starscourge Radahn and the Godskin Apostle in the Divine Tower of Caelid.
Frequently asked questions
What is Commander O’Neil weak to?
Pierce damage (0% negation). He resists Slash the most (35%), and every element is at 20%. He is immune to Scarlet Rot and Madness.
Do I need to kill Commander O’Neil?
Only if you want to finish Millicent’s questline. He is not needed to reach the end of the game.
Can you summon help against Commander O’Neil?
Yes. Spirit Ashes and co-op are allowed, and the NPC Polyanna, Adopted Daughter can be summoned from a sign near the Inner Aeonia Site of Grace.
What does Commander O’Neil drop?
12,000 runes, the Commander’s Standard and the Unalloyed Gold Needle.
Stuck on another boss? Browse all Elden Ring boss guides.
Further reading: Commander O’Neil on the Fextralife Elden Ring wiki.