Friends, first of all, you must kill the boss named Azrael, who is on the 7th floor of the Devil's Tower.
After killing this boss, he gives you the object called the Diamond Key.
(There may be differences between servers. While some servers require you to interrupt this empty space only once, on some servers you can only exit with the fallen object!)

On modified servers, it asks you for an object called Shrinking Head. You can drop this object in the same way. You can also buy it from the market on tradeable servers. You can also get it from different slots.

Just because you cut this blank does not mean you can enter. Your level must be at least 80 or above.
(It may vary from server to server. It is available on +90 level limited servers.)

Are we ready this far?
Then let's come to the detailed explanation for Satan Catacomb!

Task 1:
In order to pass this level, we must obtain the Spirit Crystal Key by killing the existing monsters...
After dropping this key, you must go to the end of the 1st map and open the seal of the Kud Statue. Since this key is timed, it will disappear within a maximum of 3 to 5 minutes. Make sure we are in the group before opening the seal. Let's do it. Your personal operations will be limited in the other mission map.

Task 2:

In order to complete this map successfully, we must break the Curse Gates. You have to do this compulsorily in order to progress in the labyrinth. There are stone pillars in front of the wrong doors. Considering these stone pillars, it becomes easier to find the right doors... At the end of the right path, you will come across Turtle Rock. To finish this map. It will ask you for the object called Shrinking Head.

Task 3:

To complete this map or this chapter, you must find the correct Retaliation Metin Stone. If you find the correct stone by cutting the Metin stones, you will be teleported upstairs for the 4th mission.

Task 4:

To finish this section, you need to find the correct path from the teleporters on the map you have entered. There are 5 different correct road maps below. It is possible to pass with help from these maps.

Task 5:

In order to pass this level or complete the mission, we must find and kill the monster called TARTATOS.

We must throw the Surat Totem we will obtain to the Obelisk. After throwing the Surat totem to the Obelisk, it will automatically teleport us to the 6th floor for the next mission.

Task 6:

In this section, we must kill all the slots on the map except the monster named Kharoon. After following the map and killing it without leaving even 1 slot, we will finally kill the monster named Kharoon. In this way, after meticulously clearing all the slots and finally killing the monster named Kharoon, we will automatically teleport to the 7th floor.

Task 7: 

In this section, we have completed the tasks completely and come to an empty place called Dr.House.
Recommendation: After clearing all the slots, your most logical move will be to head to Empty. It will be better for you if you remove your items that carry the poisoning enchantment and put them on when you have the last 20% health left...

Quotations that we found useful on the relevant subject are as follows.

Question:  How many levels can enter the Satan Katakombu map?
Answer:  +75 Levels Can Enter

Question:  How Do We Enter the Devil's Catacomb?
Answer:  You will wait after killing Azraeli. When the game throws you down, you will go towards the Yellow Tiger. When you turn to the right while going down, you will encounter the Guard NPC.

Question:  Is the Shrinking Head Required to Pass the 3rd Floor of the Devil's Catacomb Only Eplemented?
Answer: No, if the drops are unlocked, you can get them from Azrael or various events.

Question:  Are There Any New Items Arriving?
Answer:  Yes, there is. New shield, earring, necklace and bracelet have arrived.

Question:  What are the Enchantments of the Newly Arrived Items?
Answer:  While browsing some sites, a friend shared it. I will add it here too.
Soul Crystal Bracelet is 58 Lvl. Useless bonuses such as
15 Attack Speed
​​and 10 Sp change at +9

81 Lvl. Titan Shield
+9 to resist 10 skill damage. I mean skills.

60 Lvl. Soul Crystal Necklace: 28 magic speed, 10 HP change
at +9
 

62Lvl. Spirit Crystal Earrings
+9 at
14 Power
10 Damage
These are the Enchantments that will be absorbed by the sp.