On Thin Ice Witcher 3: Wild Hunt Quest
Suggested level: 30
Group: Main Quests
Location: Skellige
This quest will start after completing the "Battle Preparations" quest, at the end of which you will have the opportunity to sail to Undvik right away, or join the rest a little later when you're ready.
Every story, even the longest epic, must end, and so this one too now nears its conclusion. Geralt and his friends had acquired the Sunstone and secured the help of Fringilla Vigo. In other words, the long and dangerous process of preparing was over at last and everything was in place for the final battle against the Wild Hunt. All that remained was to summon the Naglfar to the shores of Undvik - and straight into their trap.
Prior quests
To begin On Thin Ice you must first complete Battle Preparations.
Quest stages of On Thin Ice
1. Join Avallac'h and the sorceresses on Undvik.
When you reach your destination, the camp established near the Marlin Coast village, Avallac'h will explain its plan to everyone. He will summon Eredin's ship, the sorcerers won't let it escape, you and the soldiers will attack and Ciri will wait at a safe distance.
Once everything is set up, you will be able to start immediately or you can take some time to prepare the potions, repair your equipment at the blacksmith's, which will be available in the village, and so on. You can even talk to Ciri, who you will meet near the village where she practices her skills.
2. Talk to Avallac'h when you're ready to fight.
When you're ready, talk to Avallac'h. He'll use the sunstone and summon the Naglfar.
Geralt and Emhyr's soldiers will set out to attack the ship, but they will fall into a trap, as Caranthir will freeze the whole area.
Ciri will decide to step forward and help. Avallac'h will instruct her that she must find the mage who cast the spell and destroy his staff.
3. Defeat Caranthir.
You'll be playing Ciri for a while. Run towards the ship. On the way you will have to kill a few Wild Hunt warriors and hounds of the Wild Hunt, but it won't be a big issue as Ciri activates her powers so that she can practically one-shoot them all.
Once you get to Caranthir, you'll start fighting him. When you take about 1/4 of his HP, Ciri will destroy his staff and remove the freezing spell, but unfortunately the explosion that will occur will make her unable to continue fighting. Fortunately, she will be able to teleport at the last moment and avoid being captured by Caranthir.
4. Kill Caranthir.
Removing the freezing spell will defrost Geralt and now he will be able to continue fighting Caranthir. During combat, Caranthir will be throwing magic missiles at you, and when you get close to him, he will teleport to another place very quickly. He'll also summon the ice elementals from time to time. You can fight them with your weapon, but you can also take advantage of the fact that missiles cast by Caranthir deal damage to them. When you notice that Caranthir wants to launch more missiles, position yourself so that the elemental is between you and him, and then the missiles will hit the elemental, not you.
5. Swim to the surface.
When Caranthir is close to death and Geralt wants to finish him off, he will teleport you both deep underwater where he will die. You should get to the surface as soon as possible before you're out of breath.
6. Board the Naglfar.
Go towards the ship, killing the warriors or the hounds of the Wild Hunt that will be attacking you. Or you can try to just run and get past them.
When you get to the ship, you'll see Crach an Craite getting killed by Eredin. When Eredin sees you, he will say that he wants to tell you something, but not until after the fight, when you'll be dying. The fight will begin.
7. Kill Eredin. / Follow Eredin into the portal.
Eredin will be teleporting a lot behind your back and after exchanging a few strokes aboard the ship, Eredin will summon the portal and drag you in, so you will both move to a plateau where there will be much more room.
Eredin will still be teleporting frequently. When you're far away from him, he'll attack you with various ranged spells, and when you get close to him, he'll fight with his sword.
When you take almost all of his HP, Eredin will once again call the portal and use it to return to the ship. Run after him quickly.
A few more hits and Eredin will be defeated. Before he dies, he'll tell you what he wanted to tell you that Alallac'h has tricked you both.
More and more hounds of the Wild Hunt will start coming aboard the ship, and they will surround you, but at the last moment Yennefer will appear and teleport you both on the beach. This will be the end of this quest and the next one will begin - Tedd Deireadh, the Final Age. You will receive a relic silver sword - Hav'caaren, and the Lesser Glyph of Aard.
Every plan looks best on paper. It was no different this time - though every last detail had been seen to, our heroes were still in for many an unexpected danger and difficult moment. Their division of elite Nilfgaardian soldiers was frozen in ice before it could board the Naglfar. Ciri, who was supposed to stay out of the fighting, was forced into the fray to save Geralt. Meanwhile glory-seeking, fearless (or reckless, some might say) Skelligers rushed into the bay to fight both the riders of the Hunt and the Imperial Fleet at the same time.
Despite all these complications, in the end the allies defeated the Wild Hunt and Geralt slew its king with his own hands. It was too early to rejoice, however - right before his death Eredin revealed that Avallac'h had betrayed the witcher and had his own nefarious plans for Ciri. Geralt did not know whether to trust his enemy's words - but circumstances did not allow for long and careful deliberation.
After completing On Thin Ice you will get or will be able to get Tedd Deireadh, the Final Age.