Gather plenty of loot as you climb the Citadel and find the Planetarium.
After saving your game at the checkpoint, head upstairs and into the room at the top. Take care of the Demonic Guardian to the left, then pick up the audio note to the right. Watch yourself when the Demonic Guardian abandons his armor and shield, as he’ll unleash a devastating heavy attack that has the potential to be fatal. There’s also a Human Skull in here and a forge near the door.
Leave the room and head up the stairs, disposing of the Rogue at the top on the right before grabbing the audio note on the left. Ascend the stairs nearby where you’ll be met with a Marauder, a couple of Rogues, and a Spellcaster at the other side of the hall. When you engage the Spellcaster, 2 more Rogues will pop up behind you, so be careful not to be taken unawares.
Enter the room on the left-hand side of the hall, find the 2 audio notes, then make your way through the door at the end of the hall and ignore the door that needs the 3 Small Sealed Runes to enter for now, as you won’t be able to unlock the chest beyond just yet. Instead, head to the next room, deal with the Demonic Guardian lurking over to the left and the Infected playing dead on the other side of the room, before continuing up the stairs across the room.
Pop over to the left, take out the Marauder, collect the Gargoyle and Hawk Axe and carry on up the next flight of stairs, dealing with the Marauder on the way, before triggering a cutscene and being blissfully free from enemy encounters until you see Kaslo. There’s an audio note to the left, so pick that up before proceeding up the stairs and into the next room, where you’ll find another audio note to the right. You’ll see a familiar face in here in the form of the Monk whose hand you may or may not have lopped off earlier, so have a quick chat with him and you’ll be asked to clear a path to his laboratory for him.
Follow the corridor to the next set of stairs, picking up the audio note on the way, and proceed into the room ahead to find a crafting forge and checkpoint. Save your game, the hop into the elevator that will take you to the top of the Citadel. Poke around the left-hand side of the balcony up here to find an audio note, then wander over to the guards nearby to trigger a cutscene. Request to speak to Antanas.
Board the middle lift to leave the area, go down the stairs and through the door you passed earlier that is now sans guard. The chests in here are locked, so take the stairs to the left, dealing with the Temple Guardian and Rogue at the bottom, and crack open the chest here to obtain the Harmony Buckler Shield.
Exit the room via the breach in the wall, kill the Rogue and Marauder, take the Dimensions light armour from the chest, and head through the doorway on the right. Take down the Temple Guardian and Spellcaster and carry on up the stairs. The chest and door in the room are locked, so ignore them for the moment. At the top of the stairs you’ll encounter a Demonic Guardian before triggering a cutscene.
Grab the Small Sealed Rune before retracing your steps to the Monk to notify him that his dirty work has been done. Go back to where you last saw the Captain for another cutscene, after which the side quest to slaughter his men will be initiated. Note that this is the result no matter how the conversation with him pans out. Head down the stairs and talk to the chaps at the bottom. If you lit the beacon earlier in the game, you’ll get a sweet 500 XP at this stage.
At the end of the area, use your Gauntlet to get rid of the magical barrier and head on through for another cutscene and the boss fight.