First step is making sure your server is on the third stage of the Deeplings World Change, you can check it by saying the keyword "deeplings" to the Guide NPCs
If your server is on the third stage this is the answer you will be getting from the Guide NPCs:
"The inner arcanum of the deep has been breached. Now nothing can stop the assault on Qjell's dark guardians."
During the third stage of the Deeplings World Change a new area of Fiehonja is unlocked and you will be able to start checking and defeating the deepling bosses with your friends.
There is three Deepling guardians and on every server save one boss is randomly selected.
Keep in mind that repeated bosses are possible.
- Tanjis
is the most commonly selected, followed by Obujos 
and then Jaul 
You are only allowed to battle the Deepling guardians if you delivered the appropriate amount of crates 
during the second stage of the Deeplings World Change but that does not mean you cannot check the boss of the day for your friends and server.
This is the location of each Deepling guardian lair:
The only way to find out which Deepling guardian is currently up is manually checking it, entering each boss lair teleport.
The recommended route check is: Tanjis, Obujos and Jaul. And the third stage of the Deeplings World Change stays up for 5 days.
So even if you are checking it without having crates 
done you will be able to find out which Deepling boss spawned on your server.
Here is an example: Tanjis 
as the Deepling boss of the day and the character without crates access 
done but still able to find out the Deepling boss of the day:
"To battle Tanjis, you must first prove your worth and help change the face of the deep."
"Obujos has left his lair and has not yet returned."
"Jaul left his lair and has not yet returned."
This way you can keep your friends and server informed about the Deepling bosses every day and you guys can work on them to get the Deeplings Outfit Addons 
and also for Bosstiary.
Keep in mind that they are in the Bane 
category so you need to kill 300 to fully complete the bosstiary of each Deepling guardian.
Have fun! :)
Sources:
TibiaQA.com is a fansite. Please note that the only official website is Tibia.com. The game Tibia and the website Tibia.com are copyrighted by CipSoft GmbH.
