His Better Half

 is a side quest in.

Synopsis
Ygadr came to the White March searching for his soul twin, but somebody killed him in the lonely mountain passes. I found the final wisps of his soul in the wilds east of Stalwart.

Walkthrough
As you enter Longwatch Falls from Stalwart Village, there is a torn pack directly to the north. Inspecting the pack will begin the quest to discover what happened to Ygadr.

Once you get the pack, travel directly north to the northwestern corner of the Longwatch Falls map, where you will find some hotsprings. Fight several groups of Lagufaeths, including a tougher group with a Lagufaeth Broodmother near the top of the hotspring trails. Past the Broodmother is Ygadr's journal on the ground. Pick up the journal and read it. It will point you to a cave past a waterfall. Travel to the south east corner of the map where you will find the cave on the other side of a frozen waterfall. Enter, and you will encounter the Alpine Dragon. You can either attack the dragon outright or speak with him about consuming the other hatchlings in his brood to absorb their souls. Ygadr was one such hatchling, and the dragon will admit to have eaten him.

Diplomacy
Several of the conversation choices lead to the dragon attacking. When the dragon decides to consume you, you can try to persuade it with Might 20, Perception 16, or Resolve 17 (or by using the option below them).

However, the only way the fight can be avoided at the end of the conversation is if the player has a Resolve of 17 or greater. By choosing this option, the player uses their Watcher abilities to repair the Alpine Dragon's torn soul. In return, the dragon gifts the player with Ryona's Vambraces and allows the party to exit the cave unharmed.

Fighting
You can talk to the dragon again at any time to have the option to fight him, though you should be very well prepared for this fight. If you went to the White March as soon as it became available in a new game, you could feasibly get to this point at a very low level on Normal difficulty. However, the dragon has level 14, and low level parties will stand no chance, so keep this in mind before entering the cave.

The dragon has a breath weapon that hits everything in a cone in front of it for massive cold damage, and its physical bite attacks are likewise very powerful. High cold resistance is useful for everyone, since there are also numerous additional enemies in the form of regular and greater Ice Blights and Frost Oozes, in addition to summoned Spectres. The dragon is also able to Sneak Attack and has Deathblows, which it can easily use on your characters since the other enemies in the room inflict conditions, such as stun, that allow for sneak attacks.

Loot
There's a treasure hoard directly behind the dragon which contains Sabra Marie, the Black Sanctuary and Ryona's Vambraces if he hasn't already rewarded you. If you attempt to take any item from this hoard, the dragon will yell "Thief!" and attack.

Different from that, a skeleton to the left of the dragon holds a hidden treasure cache which can be looted safely.