This is the most fuckable quest on calpheon :
1) Take the quest from Black Spirit and go to falasi - https://bdocodex.com/th/quest/3125/1/
2) when you finish all chain you will get LAST 3 QUESTS, ( something treasure , another shit and ancient ) . NOTE THAT YOU NEED TO TAKE LAST QUEST - SOMETHING ABOUT ANCIENT CIVILISATION BOTTON ON THE SEA ****
3) If you did it right, after the quest is done, it will a appear another quest chain from falasi - https://bdocodex.com/th/quest/3128/1/
4) do the chain and get the knowledge
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IF YOU DONT HAVE THE KNOWLEDGE and you did it years ago Mysterious Request - the only option is to install a bookshelf like Handcrafted Serendia Ecology Bookshelf - BUT KEEP IN MIND THE CHANCE TO GET IT IS LIKE 0.000000000001% because of the total amount of ingame knowledge base

You can complete the following questline to get the knowledge:
https://bdocodex.com/th/quest/3125/1/

After u did the above questline another quest will immediatly start and you need to finish that one.
You get the knowledge from the following quest:
https://bdocodex.com/th/quest/3128/7/

+ Можно выполнить с Дайном Грез. Будут посылать туда-сюда с материка на острова.
Приготовтесь потратить много времени.