With two Splinters now recovered, Deckard Cain turns his attention toward Aidan, the warrior who eventually became the vessel for Diablo himself.
Finding Aidan leads us to another Waking Nightmare, this time revisiting the original Diablo and the labyrinth beneath the town of Tristram.
The Brother’s Keeper ultimately puts you face to face with Diablo as you attempt to recover the final Splinter needed for Cain’s investigation.
How To Get The Brother’s Keeper Quest?
The Brother’s Keeper becomes available after completing The Burning Shepherd and collecting the Splinter of Hatred at the end of the Durance of Hate Waking Nightmare.
Return to Deckard Cain at the Imperial Library and speak with him to learn that your next target is Aidan, who can be found within Scosglen.
Cain points you toward the Strand, with the Corbach Waypoint providing a convenient starting point for reaching the marked location.
The Brother’s Keeper Quest Walkthrough
Travel to the Corbach Waypoint and make your way toward the marked location in the Strand, where you will eventually encounter Aidan and begin fighting him.
Deplete Aidan’s health to end the encounter, after which he will reappear nearby and can be approached without becoming hostile toward you again.
Speak with Aidan to continue the quest, which causes his Waking Nightmare to appear and allows you to enter Diablo – The Labyrinth.
Enter the Waking Nightmare and begin fighting your way through the Labyrinth, following its passages while dealing with the various demons blocking your progress.
Several familiar enemies from the original Diablo appear throughout the journey, but your main objective is to continue descending until you eventually encounter Diablo.
Once you reach Diablo, approach him to begin the main boss encounter and prepare for several phases before he can finally be defeated.
Attack Diablo while avoiding his incoming abilities until you deal enough damage to complete the first phase, causing him to temporarily become invulnerable.
Several Portals of Darkness will appear around the area during these phases, and you must destroy them before Diablo becomes vulnerable to your attacks again.
Repeat this process of damaging Diablo and destroying the Portals of Darkness whenever they appear until you eventually deplete all of his remaining health.
After defeating Diablo, approach Aidan and speak with him as he prepares to continue searching for his brother and finally put him to rest.
Aidan will leave after thanking you for your help, leaving the Splinter of Terror behind for you to collect and complete The Brother’s Keeper.
Pick up the Splinter of Terror and use the portal that appears afterward if you wish to return directly to the Imperial Library.
The Brother’s Keeper Quest Rewards
Completing The Brother’s Keeper rewards you with XP and Gold, with the amounts received scaling based on your character’s current level when finishing the quest.
You will also obtain the Splinter of Terror, adding the final Splinter to those previously recovered from the Worldstone Keep and Durance of Hate memories.
Legacy of Hope becomes available afterward, serving as the final quest that brings the Season 15 Seasonal Questline to its conclusion.
Verdict
The Brother’s Keeper takes us further back through Diablo’s history by recreating the Labyrinth and eventually placing us against the Lord of Terror himself.
Diablo’s Portals of Darkness make the final encounter slightly different from a straightforward boss fight, since they must be destroyed between damage phases.
With the Splinter of Terror finally secured alongside the other Splinters, we can return to Deckard Cain and finish the storyline with Legacy of Hope.
