The Nidhogg, Clan of the Dragon Add-on for Northgard has 7 achievements.
Get 50 Victories with Clan of the Dragon
Win with the Clan of the Dragon
Enslave a Jotunn, a Kobold or a Myrkalf
Endure a Thrall uprising
Build the Relic of Skull of Hrungnir
Kill a Jötunn with a Draconic Jötunn
Finish a Conquest with the clan of the Dragon