Hellbound Stage 11 - Tully's Workshop
After having left the Tower of Infinitum and turning a few corners, you will reach a place similar to the way to the Pagans' Temple in Rune. Here you can find NPC Dorian. If you have finished the quest "Matra's Curiosity", however, and brought the Dwarf his two blueprints, you can search out the NPC Deltuva near the Outer Gate of the Steel Citadel, who will port you directly to Dorian, so that you don't have to fight your way through the Base Tower and the Tower of Infinitum again. Dorian in turn teleports you into Tully's Workshop. It is of great advantage to bring along a Spectral Dancer who has learned the lvl 77 skill "Dance of Shadows" (on that later more).
Tully's Workshop consists of eight floors where you have to find key monsters, trapdoors, and methods to unlock the next floor. Those trapdoors are actually traps in a Kamael sense. It is possible that a female Kamael might be able to use Detect Trap to find them easily, but that has not yet been confirmed.
First floor:
Each room has monsters who fight in groups. You can start the combat by using the stairway to move to the top or by choosing one of the rooms on the periphery to enter.
Master Zelos is the key monster on the first floor. After killing him, the trapdoor to floor two will be unlocked. This room does not have a door, so you'll have to find the stairs (via a passageway in another room), climb on the wall and circle around along the periphery until you see the room with Master Zelos. Drop down into it and kill him.
Then, before you teleport up to the second floor, be sure that your Spectral Dancer has danced the Dance of Shadows. Both on the second and on the fourth floor you will be received by aggressive monsters and that Dance will make you invisible to them as long as you leave them alone.
Second Floor:
One possibility here is to hunt a little in each room, because one of the rooms has a hidden trapdoor that lets you move to floor three. Search in the corners. After teleporting to floor two, get out of the "reception room" and go in the one straight in front of you. Once in the room you go in the left corner and run into the wall - you should get ported to the next floor.
Actually there is no need to kill monsters. Just use the Dance of Shadows. If you really don't find the trapdoor, check the corners of each room.
Third Floor:
Master Festina will appear on the central platform, with many monsters around her. If you attack Master Festina, all of the monsters inside the room will react. Thus, the less dangerous way is to clear out the other monsters first.
This is a straightforward hard fight. When you are attacking the Boss instead of the minions, the latter will rush up, and if you are not taking out the minions fast enough, you are in trouble, as they respawn quickly. You should try to find a balance - kill a certain number of minions and then concentrate your attention on the Boss again. But you need to hit hard, with strong attacks; in the Steel Citadel, Elemental Attributes on both weapon and armor are very important.
After Master Festina dies, a trapdoor in the central platform where she spawned will be unlocked, which allows you to move to the next floor.
Fourth Floor:
Again there are two possibilities: hunt a bit in every room or use the Dance of Shadows. One of the rooms has a trapdoor (here you might even see it, labelled "Trapdoor") that leads to floor five. Search in the corners, like on floor two.
Fifth Floor:
Floor five is composed of a very narrow labyrinth you have to cross from the outside to the center. There are also pillar-shaped devices that can open doors in the labyrinth - they are called Tully's Gatekeeper.