On Thin Ice in The Witcher 3: How to Beat Caranthir and Eredin (Final Battle)
Witcher 3 On Thin Ice: the point of no return, playing as Ciri, how to beat Caranthir and Eredin, known bugs, and the Hav'caaren reward.
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Updated October 2026. On Thin Ice is the final battle against the Wild Hunt. The Sunstone calls the Naglfar to Undvik, the plan goes wrong, and you play as Ciri and then Geralt through two boss fights: Caranthir, then Eredin himself. There are no ending choices in this quest, but talking to Avallac'h at the boat is the point of no return, so prepare before you do.
Quick answer
Point of no return: talking to Avallac'h next to the boat on Marlin Coast. Repair, stock potions and finish anything you want first.
Ciri: you play her first. Enemies respawn endlessly, so just push forward to Caranthir and take a third of his HP.
Caranthir (Geralt): make his projectiles hit his own Ice Elementals. You can meditate right after the fight.
Eredin: punish his ranged attacks, use Igni if he's covered in ice, and follow him through the portal quickly.
Reward: 500 XP, the Hav'caaren sword and a Lesser Glyph of Aard.
Before you talk to Avallac'h at the boat: this is the point of no return. Also, the very early contract Devil by the Well may fail if you haven't finished it before this conversation, depending on your ending. The Nilfgaardian camp's services (the quartermaster is a journeyman blacksmith) disappear once the battle starts.
On Thin Ice Walkthrough
1. The Camp on Marlin Coast
The team arrives at a Nilfgaardian camp on Marlin Coast, where Avallac'h explains the plan. He won't let Ciri fight, whatever you say. If you romanced Triss or Yennefer, Geralt gets one more conversation with her (see our romance guide). You can also find Ciri training on the path south of the camp.
The camp has alchemy ingredients and weapons inside the buildings. Don't loot the containers outside: the game counts it as stealing and the soldiers attack. If it happens, run off and come back; they won't attack again. You can still travel, gather ingredients and do side quests before you talk to Avallac'h.
2. Play as Ciri
Talk to Avallac'h at the boat when you're ready. He and Ciri use the Sunstone to call the Naglfar to Undvik, but Caranthir freezes everyone. Ciri breaks free and you take control of her with her Elder Blood power active: she kills Wild Hunt enemies in one hit, and Blink wipes out up to 5 at once. Enemies keep spawning, so just keep moving.
When you reach Caranthir, you don't have to kill him: knock off about a third of his HP and a cutscene plays where Ciri breaks the orb on his staff. The blast knocks her down, and Geralt thaws out just in time.
Boss Fight: Caranthir
| His move | What to do |
|---|---|
| Magic projectiles | Dodge and keep moving. Put his Ice Elementals between you and him; his attacks hurt them too. |
| Teleports away | Expect it at regular intervals and close the gap again. |
| Summons Ice Elementals | At about half health and again at low health. Avoid them rather than fight them. Igni and dodging help. |
| Ranged pressure | Quen, or Yrden with the Magic Trap ability, blocks his projectiles (see our signs guide). |
Don't save your potions and bombs for Eredin: you can meditate with no time passing right after this fight. At about 5% HP, a cutscene plays: Geralt runs him through, and Caranthir drags them both underwater. Swim to the surface fast; a Killer Whale potion buys extra time.
3. Reach the Naglfar
Meditate if you need to, then push northeast toward the Naglfar. Enemies keep spawning along most of the path, so only clear what blocks you. You pass Udalryk and Hjalmar on the way. At the Naglfar, a cutscene shows Eredin killing Crach an Craite, then he turns to Geralt.
Boss Fight: Eredin
| Phase | What happens | Tips |
|---|---|---|
| 1. On the Naglfar | He teleports like Caranthir, casts magic at range and uses his sword up close. | Wait for his ranged attacks: he stands still and is open. He staggers easily, and Quen's Exploding Shield helps. |
| 2. The icy plateau | After a few hits he throws Geralt through a portal. | Dodge his ground waves and orbs. If he's covered in ice, melt it with Igni so you do more damage. |
| 3. Back to the Naglfar | When he's nearly beaten he opens a portal back, and large projectiles start falling. | Run to the portal immediately and finish him. |
Eredin is very good at parrying. Whirl works only if you time it; spamming uncharged Rend lands hits he can parry but not counter. Fast attacks (stabs) are safer than long combos. For general tips, see our combat guide.
At the end, Geralt plucks out Eredin's eye with his own pirouette and cuts him down. Eredin claims Avallac'h played them both to get Ciri, then dies. Yennefer pulls Geralt out through a portal as the hounds close in. The quest ends with 500 XP, Hav'caaren and a Lesser Glyph of Aard, and Tedd Deireadh, The Final Age begins.
Known Bugs
- Caranthir freezes after the switch from Ciri to Geralt. It's random: reload the checkpoint, or if he still takes damage, keep hitting him.
- Eredin seems immortal: if you're very overleveled (or on New Game+), you can bring him down before the scripted portal. Just wait; it can take close to a minute.
- Camp fires show a "Loot" prompt instead of "Extinguish". There's nothing to loot.
Video: On Thin Ice
Frequently Asked Questions
QWhere is the point of no return in On Thin Ice?
Talking to Avallac'h next to the boat on Marlin Coast. Until then you can still travel and do side quests.
QAre there ending choices in On Thin Ice?
No. Ciri's ending is decided by earlier choices, such as the ones in Child of the Elder Blood. See our endings guide.
QHow do I beat Caranthir?
Keep moving, make his projectiles hit his Ice Elementals, and block with Quen or Yrden. Use your potions freely; you can meditate right after.
QHow do I beat Eredin?
Punish his ranged attacks, use Igni when he's iced over, prefer quick attacks to long combos, and jump through his portal fast in the last phase.
QWhy won't Eredin die?
If you're overleveled, you can deplete his health before the scripted portal. Wait up to a minute and the fight continues.
QWhat do I get for On Thin Ice?
500 XP, the Hav'caaren sword and a Lesser Glyph of Aard.
Before this: Battle Preparations, Veni Vidi Vigo, Child of the Elder Blood and Skjall's Grave. More: all endings and all Witcher 3 quests.
Sources: in-game quest text and journal; steps, boss tips and rewards checked against the Witcher Wiki and Fextralife pages for On Thin Ice. Screenshots: gameplay frames from YouTube walkthroughs by Kaon Fong, ECSESS Games, 2Hot2Handle, Sickdistic, AFGuidesHD and H gaming channel.
Kai Mercer covers game news, free games, release calendars and guides for xGamerss.
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