During Act II, you will be exploring the Shadow-Cursed Lands until you eventually find a way to weaken Ketheric Thorm, which allows you to deal real damage to him.
After the whole journey in the Shadow-Cursed Lands, defeating Ketheric Thorm sets you on a path to find the other Netherstones.
These will be with Orin and Gortash, who have made their way to Baldur’s Gate as the siege is about to begin and you will need help.
How To Defeat Ketheric Thorm?
Ketheric Thorm is known to be immortal and rules an army of different creatures, which makes the battle at Moonrise Towers chaotic.
Before you will be able to hurt him, you will have to find and free the Nightsong, who leads an assault on Moonrise Towers and makes him vulnerable.
You later pursue Ketheric Thorm deep within the tower into the Mind Flayer Colony to defeat him once and for all with the help of the Nightsong, who you need to free again.
Where To Go After Defeating Ketheric Thorm?
After you have defeated Ketheric Thorm, you need to make your way to Baldur’s Gate where you will need to do the Gather Your Allies quest and find the other Netherstones.
This requires you to head to the road to Baldur’s Gate, which was previously inaccessible and would lead to you getting captured. (A crow would appear to attempt to tell you to turn back)
To make your way to Baldur’s Gate, you will need to bring the Netherstone with you or else you will become enthralled, resulting in a game over.
Road To Baldur’s Gate Location
The Road To Baldur’s Gate can be found to the west of The Waning Moon and the House of Healing, which are on the left side of the Shadow-Cursed Lands map.
You may have already unlocked this if you explored the area, which should allow you to use the waypoint to get there faster.
After you have defeated Ketheric Thorm, you may head to the Road To Baldur’s Gate to proceed to Act III.
Verdict
Defeating Ketheric Thorm is a big step in progressing to the final parts of the story and is only a taste of the challenges to come.
You will eventually have to improve your character’s equipment and should have them leveled up to withstand the fights that you will encounter.
Proceeding to Act III will cause the Shadow-Cursed Lands to be restored if you have retrieved Thaniel from the Shadowfell.