When Scarlett first reaches the Administration Center area of the Arsenal District, halfway up the great stairs, she will see Brother Johan being chased away from the Administration Center. If she speaks with Brother Johan, he will give her both this quest and the closely related Of Cursed Chapels quest.
This quest is mandatory. Scarlett will need to complete it in order to obtain Mental Skills she needs (The Whisper) to complete the The Voice of the Dead quest for Liora, which in turn allows her to gain access to Largo and the Old Chimney, which is all part of the Chasing the Black Grimoire quest.
Scarlett should return to the Inner City. The only way into the Old Cathedral is through the Inner City Catacombs. There is only one entrance to the Catacombs, at a sewer outlet on the canal, under the bridge by the Tavern. Scarlett should go down into the Canal and swim to the entrance, going into the catacombs. (Click on map to enlarge.)
In the Catacombs, Scarlett has a choice of routes. If this is her first visit to the Inner City Catacombs, she may want to explore both to collect treasure and slay the many Grippers wandering about. To reach the Old Cathedral, she will eventually need to cross an elevated bridge over a larger cavern, dealing with both Flying Beasts above her and Assassins below her.
Lastly, she will need to use her warhammer to knock down a door. The room beyond is infested with three Lectors, but leads to a red-glowing tunnel that is the way to the Old Cathedral. (The other door in that chamber, requiring a special key, can only be accessed if Scarlett is a member of the Order of the Holy Seal and has accepted The Sword of St. Anthony Quest to get the special key.)
|Note: If Scarlett hasn't already visited the Old Cathedral, she should, of course, use the Gateway Idol here to obtain the Unworldly Clutch Necromantic Skill by collecting the three fragments (two on the lower level, one on the upper side.) After she has used the Gateway Idol, a Necromancer will appear and animate those Skeletons to attack her.|
To exit the Old Cathedral, Scarlett may either return through the Inner City Catacombs, or she can use her warhammer to smash the debris piled against the door at the upper level and exit directly to the Inner City.
Scarlett should return to Brother Johan in the Arsenal District and give him the sacred scrolls to complete the quest. This time, she will find Brother Johan in one of the residential rooms, one level higher than where she first met him. The door is unlocked. (Click on map to enlarge.) Brother Johan will then immediately use the sacred scrolls to remove the curse blocking entrance to the Chapel, sending Scarlett on the Of Cursed Chapels quest.
- Of Cursed Chapels - Brother Johan asks Scarlett to slay the "demons" (Lectors) in the Arsenal District's Chapel. Scarlett received this quest at the same time.