Divinity: Original Sin 2 - Definitive Edition
97 Achievements
GOG
Thunders of the Upper Deep
Escape the kraken's clutches
78.3%
How to unlock the Thunders of the Upper Deep achievement in Divinity: Original Sin 2 - Definitive Edition - Definitive Guide
This is not missable and will be unlocked once you complete the ship, essentially the game's tutorial.