Keystone - Reinforcements | Side quests Lords of the Fallen Guide

In the narrow passage, you find a Blood Flintstone.

After you complete this side quest, at the Citadel, there appear reinforcements that help you fight Rhogars.

After you defeat the Commander, head up the stairs (opposite the gate that you entered through) and after a short conversation with the Captain [M2.6] take the path to the right. After you take another turn, as far to the right as possible, you will note an active portal. On the left, there is a narrow passage with an opponent behind a shield (watch out for his quick jabs from behind the shield). You will find a Blood Flintstone here [M2.7], which you are going to need later in this quest.

A stack that you can set on fire.

As you head on, you will reach a checkpoint. On the right, there is a passage to the External Walls, go there. As you go down the path, you encounter more opponents with shields (you can get one of them from behind), and you will be able to go left, at the smaller passage before the gate. On top, defeat the Crossbowmen, and set the wooden stack on fire [M2.8] (1000 EXP, you need to own a Blood Flintstone).

Knights that you can talk to, at the Citadel, after you leave the Catacombs and clear the Planetarium beforehand.

Later into the game, from the Catacombs, you will have to make it to the Citadel. Then, you will have to make it to the very top and talk to Kaslo (along your path, you will be passing by fighting knights). Finally, after you have cleared the Planetarium, climb down the stairs and before the entrance to the Main Hall, you will see (and hear) two soldiers talking about what they have seen. Talk to one of them and you will earn 500 EXP.