DOS2:Call to Arms

Call to Arms is a quest in Divinity: Original Sin II. It is initiated upon saving Gareth in More Dangerous When Cornered.

Objectives

Speak to Sir Gareth at Amadia's Sanctuary.
Sir Gareth made it back to his Seeker comrades. Their leader has returned. What does he plan to do next?

Find Purging Wands.
Only a Purging Wand can destroy a Shrieker.

Return to the Seekers at Amadia's Sanctuary.
We found a Purging Wand.

Speak to Gareth.
From their rallying-point at an old Magister camp, the Seekers will seize the ship while we attack the Magisters on the shore.

Destroy the Shriekers.
Regrouped at an old Magister camp, the Seekers are counting on us to clear the Magister defences on the shore.

Give the Seekers the go-ahead.
The Shriekers destroyed, the Seekers can launch their attack.

Walkthrough

After saving Gareth in Most Dangerous When Cornered, he will relocate to Amadia's Sanctuary. There, when you talk to him, he will inform you that he needs a purging wand to get rid of the Shriekers. You can find a purging wand various ways:

1. Pickpocketing it from Radeka or killing her
2. Finding one in the Vault of Braccus Rex
3. Using Braccus Rex's Tyrant's Helm from Artefacts of the Tyrant

Once you have a purging wand, tell the seekers in Amadia's Sanctuary. A majority of them will relocate to the Abandoned Camp in the northeast part of the map, newly labeled 'Gareth's Rallying Point'. Using the wand, purge the two shriekers directly north of the camp. The shriekers on the right are optional.

Note: If you gave Slane Radeka's purging wand and kept him alive, he will purge these two shriekers for you.

Through the gates at   X: 561  Y: 285  , Bishop Alexander and other magisters can be found. Once you have attacked the magisters, the quest will end.

Tutorial

1. Save Gareth in Most Dangerous When Cornered
2. Teleport to 'Amadia's Sanctuary' and talk to Gareth
3. Find a purging wand
   1. Pickpocket from Radeka or killing her
   2. Find one in the Vault of Braccus Rex near where Trompdoy's soul jar is
   3. Use Braccus Rex's Tyrant's Helm from Artefacts of the Tyrant
4. Tell Seekers you have a means of purging shriekers
5. Teleport to 'Hollow Marshes - Abandoned Camp'
6. Go north and purge the shriekers Note: If you gave Slane Radeka's purging wand and kept him alive, he will purge these two shriekers for you
7. Enter combat with the magisters and Alexander