Santa Quest to unlock Duhvic
This guide will help you unlock Duhvic, you'll need to help a snowman by killing Evil Santa.
To be able to do this questline to unlock Duhvic, you'll need to do Ancient Lands Quest to unlock Aynor.
Once you finished the previous quest, a red portal will appear at your left.
Enter the portal then go north, whenever you can go west, then south and finally east (check the image below because that doesn't make any sense).
Once you reached the snowy zone (Yontil Pass), you'll get a freeze debuff that makes you walk slow and takes some dmg don't worry (no need to waste your time making snow potions for that).
Go top-right of the map and walk behind a tree (it has an invisible teleport).
Then you'll have to talk to a snowman called Sherpa, he'll ask you for help.
Go north from there and enter the castle with a red flag.
First of all talk to Santa's Helper, avoid killing Santa's Elf for now, because you need to talk again to the snowman first.
After returning from the snowman you'll need to get Candy Keys to fight Santa, they're dropped from Santa's Elf (5% drop chance). Yo can farm them at the castle or the underground zone (ladder before the castle).
You have two options to fight Santa, ask for help or solo. If you have to go solo get ready some potions or food and more candy keys. I suggest you to do a dummy run to see how many dmg you deal to Santa and farm keys and food based on that. Santa is located in the castle, right door (entering it'll destroy the candy key forever, so just 1 key and rest food each run).
If you're a ranged user fighting Santa, just focus on him avoid the adds and don't let them hit you. Repeat this until you kill him and go back to the snowman.
To get to Duhvic get down the ladder that appeared at your right (if it doesn't appear try reset cache option in settings and relog).