Cerberus/Kelberos Nest Guide
Introduction
I know this is kinda early to post when the Lv32 cap isn’t even out yet. Even when Lv32 cap is released, the Cerberus Nest may not be released probably at least 1 or 2 months more. But nevertheless, let’s get some heads up regarding this new nest!
When your character reaches Lv32, you can get the related Cerberus quest from the NPC in Saint Haven (He should be either Bailin the Blacksmith, or the Dishonest Trader Bob). You will receive a Nest Entry Card (Dark Lord Stamp) from him. This Dark Lord Stamp can be obtained through the Dimensional Rabbit Chest from various Lv31 Abyss Dungeons.
Similar to the Red Army Commander Stamps of the Mino Nest, these Dark Lord Stamps can be traded too. You can enter the Nest 5 times per week. As long as you don’t kill the final Cerberus Boss, the nest won’t be counted. Upon killing it, it will drop a Dark Lord Amulet, which is a Nest Entry Card to enter the Cerberus Nest HELL mode.
Important Pointers:
1. Throughout the Nest run, it will not drop any equipment for the classes except for various Epic Accessories. This means that there isn’t a need to get 4 different classes for your team, unless there is a choice for powder hunts.
2. The only potions useable are Cash Shop MP Potion, Normal HP Potion and Normal MP Potion.
3. The Nest run can be rather long. If you don’t have 32B equipment or higher, please remember to bring more MP potions along to prevent yourself getting out of MP.
4. The Nest has 6 different stages. Players will have to kill all the monsters in the area before being able to get to the next stage. In order to proceed to the next stage, all members must be present at the door. If not, the door will not be opened (Exceptions: Stage 1 and 2).
Stage 1
The 1st 2 gatekeepers are the 2 bulls you have seen before in the Minotaur Nest. Except for the fact that, now they are more powerful with a few new skills.
When the white minotaur is on the verge of death, it will cast a speed-up spell to increase the attack speed of monsters around it, including itself. Hence, please focus your firepower on the black minotaur first, while one of your team member lures the white minotaur away temporarily.
When the black minotaur is almost dying, it will cast a mighty swing. Although the damage is high, if your team’s firepower is good enough, it will not be able to cast the skill successfully.
When the black minotaur dies, the white minotaur should be easy to kill now.
HELL MODE: The 2 minotaurs will cast various strong buffs at the start. After some time has passed, they will summon several orc minions from a side gate.
Stage 2
The monsters from the 2nd stage consists of numerous bomb-throwing Goblins and Orcs. The biggest threat that players are facing, are the Bombing Orcs and the Orc Warriors beside them So after players have jumped down the broken bridge, please use your various AOE skills on the Orcs. Ignore the other monsters beside you. Once you have killed those bombing orcs, the threat will be reduced greatly.
The aim to stop these bombing orcs, is to stop them from throwing long range bombs. The damage may be weak, but they can potentially interrupt your casting of skills.
Usually if all the team members focus their firepower on these orcs, they should be pretty much dead already.
The only problem left is the Goblin King now. This Boss is similar to the Boss in one of the Abyss Dungeon (should be a Lv26 or Lv28 dungeon). The Boss will not be interrupted by normal attacks, so simply spam all your skills in order to stop him from retaliating. His retaliation attack can be quite painful.
When the boss is dying, it will cast Berserk to increase its speed and attack. In the mean time, it will cause damage to surrounding players. So once you see the Boss is going to get up, do not stand right in front of the boss. Once you get hit, and your team members cannot manage to stop the Boss’es action, you can be combo-chained by the Boss and lose a huge amount of HP.
This stage should be fairly easy, just that players should avoid solo-ing the Boss unless they are good enough. Remember to clear all the small mobs first before ganging up on the Boss.
HELL MODE: There will be more bombing monsters in the stage, except that you can’t hit them! They are located right above you. So you should always try avoiding the incoming bombs from the sky. If you are hit by these bombs, it is likely that you will lose lots of HP when other monsters get to you.
Stage 3
In the beginning, players will see corpses of various skeletal monsters, but there isn’t a need to bother them for now. Just get closer to them to activate the 1st half sequel of the stage.
1st Half Sequel
When the dark crystals around the skeletal warriors break, you can start attacking them. At this time, the boss is invincible. It will hide behind the stage to attack the players. As long as players don’t stand near the stage, the boss would not be able to attack you.
Usually the boss will only lock on on one player. Once the player is locked, the boss will be facing that player all the time. If you are able to find out who is being locked on, as long as the player does not get near, the boss will never attack the other players. The other players will simply have to kill those skeletal warriors.
Once those skeletal warriors are killed, the Boss will come down from the stage and revive the corpse of the surrounding skeletal monsters. At the same time, various types of ghouls will be summoned along to attack the players. Take note that once the monsters on the field are being reduced to a certain amount, the Boss will re-summon them. So at this time, you simply have to focus your firepower on the Boss. Killing those small monsters will not benefit much.
2nd Half Sequel
When the Boss is casting Blood Rain, the difference from the normal dark castors is that the AOE of Blood Rain will be extremely big if the place that the Boss is casting is the position that it appears once the skeletal warriors are killed. The Paralyze Resistance of the Boss is extremely high during the spell cast too. Hence the best way of tackling the boss would be sustaining him in the air all the time.
If unfortunately that the Boss manages to cast Blood Rain, focus all your firepower on the Boss in attempt to interrupt the casting. If not, the players with bad equipment will be devastated. When the Boss dies, all the minions will disappear.
HELL MODE: The things to note here are the Blue Ghouls’ Freezing Attack, and the Red Ghouls’ Self Explosion Attack. If you have played the Ghoul Mode PvP, you should know what these skills are. Because of the attacks of the monsters will become even more frequent, it is likely that players will get their skill interrupted. If you get hit by the explosion, you will lose quite a lot of HP too. So when you’re focusing your firepower on the Boss, take note of these Ghouls as well. 
Stage 4
At the 4th stage, players will be in a big arena in which various monsters will be spawned from the 3 different portals. This stage is rather simple, because all you have to do is to clear all these small minions.
(The whole description on the 3 spawns  of monsters is kinda redundant in my opinion, hence I did not translate them but only those important points.)
The Maneaters from the final wave spawn, have a rather low accuracy. As long as players do not get near them, players should be fine. Take note of their jumping attack as well. Sometimes, these monsters’ attack may hit their own companions. The damage may be low, but they will also interrupt their own companion’s attack.
The thing to note here is that, this stage can potentially drain most of your MP away. It would be better if players try to gather together and let the monsters gather too. Then use your various AOEs to finish them off. If your AOEs are on cooldown and they are not dead yet, run around and wait for your skills to cooldown and repeat. These monsters have a rather slow movement speed. As long as players continue to move, basically they can never catch up. This stage is probably the easiest stage in the Nest.
HELL MODE: I guess the only difference is the monsters are stronger with higher HP, defenses, and heals. It probably spawns more monsters.
Stage 5
Probably the most interesting stage out of the 6 stages. This stage has a special requirement to clear, and that is the difference between the 2 Maneaters death time should not exceed 10 seconds. If the time exceeds 10 seconds, the dead Maneater will be revived once again.
So if players wish to get a SSS out of the Nest, you can make use of this point and revive the Maneater endlessly until you get a high point.
Usually, 2 players will tag together on each boss. So if one of the team does not have sufficient firepower, that member can choose to go over and help, or simply drop his firepower at the moment. The thing to note here is the damage from these Maneaters is quite high. The easier one is the left Poison-Maneater, which will vomits poison out of him. Compared to the Mino-Maneater, the Poison-Maneater is easier to dodge. If I remember correctly, the right one is weak to light attribute. So clerics can clear them faster.
HELL MODE: The Maneaters’ damage will be raised significantly, and the time difference is now reduced to 5 seconds! If the time exceeds 5 seconds, a 3rd Maneater will be spawned. Not only that, they also have heals. This stage is rather difficult compard to the normal mode.
Stage 6
Actually the difficulty of this Cerberus Boss is not that high. Because usually only one person has to dodge its attack, and it does not have many huge AOE attacks. As long as you are not being targeted by the Boss, simply stay beside him and attack.
Cerberus Skills:
Pouncing Attack: When players are rather far away from the boss, it will lower its body and then pounce towards the player.
How to dodge:The prior action of the pounce is quite obvious. It is easy to dodge by dodging sideways.

Raging Howl: The 3 heads will close their eyes while contracting their body. Then they will release a strong howl that forces players away from him.
How to dodge:The damage of this skill is extremely low. You don’t really have to dodge the skill anyway. Of course, players can use strong Paralyze Resistant skills to prevent themselves from being blown away.

Claw Attack: If you are facing the Boss right in front, you will see his left paw being moved behind followed by a huge frontal sweep.
How to dodge:By staying at the right side of the Boss, you will not be hit. If not, simply use your dodge.

Clap: The Boss will raise its left or right paw high, and slam it down.
How to dodge:When the boss is preparing this attack, simply by moving away is sufficient.

Back Kick: Using its hind legs to make a big sweep on his back.
How to dodge:Stay beside the Cerberus, the middle portion closer to the front.

Revolving Kick: The boss will suddenly jump up and turn in circles, and deal huge damage (DNB: I have cleared this Nest numerous times and I have never ever seen this skill before).
How to dodge:This skill rarely appears, and the damage isn’t that high. Those who get hit by this, it is just your luck.

Fireball:Coughs out numerous fireballs in a fan shape manner. It comes from the head of the boss on your right.
How to dodge:Never ever stand right in front of the head, you can easily get killed instantly. You can easily avoid these fireballs by going to the left side. If not, simply look for where the fireballs are coming, and move yourself away from them. The fireballs are rather slow.

Dark Lightning: The head of the boss in the middle coughs out a long range frontal dark lightning in a straight line.
How to dodge:Not really a strong damage skill, the AOE isn’t that big either. Stay away from the middle and you should be safe. If not, dodge sideways to dodge the attack.

Ice Ball:Shoots out 2-4 homing ice balls that freezes players upon hit.
How to dodge:Theoretically speaking all players will receive an ice ball from this skill, but some may disappear suddenly. Just continue moving away from the Ice Ball at one direction and you will never be hit.

Falling Lightning: Prior to casting this skill, the Boss will raise its frontal half body and slam its paws on the ground heavily. It will turn the sky dark and summons numerous lightning hits from the sky around him.
How to dodge:The damage is rather high. As long as you are extremely close, or extremely far from the boss, you will not be hit. Take note that its paw slamming skill can be avoided by jumping if you are close to it.

Falling Ice:The Boss will emit blue light from itself, and summon various ice shards to fall on the ground targeting 1-3 players’ positions. The ice shards will stay on the ground for a certain time before disappearing. Upon touching these ice shards will reduce your HP and speed.
How to dodge:When you see the blue light emitting, start moving and don’t ever follow your team members. If you are following so closely to your team member, you may get all the ice hits on yourself.

Volcano Eruption:When the Boss emits red light and some flames from him, it will soon be bursting flames all around him. The damage is extremely high.
How to dodge:Notice that the boss will first close its eyes, followed by contracting its body with flames around him. Run away from him immediately, tumble/blink/dash/slide whatever you can do. After about 3 seconds, it will summon flames all around him (similar to EL’s Firewall).

When the Boss left 1 bar of HP, it will summon various hounds. These hounds can be quite painful with their bites and pouncing attacks. They will revive after the die too. So focus all your firepower on the boss!
HELL MODE: For normal mode, the Boss will only use its elemental attacks when it loses 1 bar of its HP. However in Hell Mode, the elemental attack starts immediately. The frequency of these attacks is rather high too. Hence, players will have lesser chance to get close to the Boss. Its damage will be raised to 4-5 times than the normal mode Boss.
Lightning Charge:It will summon several balls of lightning right in front of it.
How to dodge:Don’t ever stay right in front of him for long.

Ice Mist:Channels a mist of ice right in front of it.
How to dodge:Don’t ever stay right in front of him for long.

Fire Run:Similar animation as Volcano Eruption, but this time it will run forward and leaves flames behind him.
How to dodge:Don’t ever stay right in front of him for long.

In short: Don’t ever stay right in front of him for a long time.
Rewards:
1. As mentioned above, Epic Accessories will drop from various Bosses (Likely to be Minos and Cerberus).
2. Epic powders to craft various prefix effects.
3. Materials to craft the Cerberus Equipment Set, like Cerberus Skin.
4. Epic equipment. (Epic Armors from Normal Mode, Epic Weapons from HELL mode.)
5. Epic Heraldry Enhancement Plates, and Special Skill Heraldry Plates (Dark Lightning, Ice Ball, Fireball).
Note: This guide is being translated and edited from the below stated URL, as well as addition of various information not stated in the link. Some information may be incorrect, but only to a very little bit. Please correct me if there is any errors.