Hello!
Recently, I posted a lore thread here, about the Owls. Now I’m sharing some lore material about Medzio Diena. (I’m going to post more images later 
)
According to the ToS website and NPCs who talk about it in Klaipeda and Orsha, Medzio Diena is a cataclysmic event that happened four years before the current time during 1091. On this day, a giant tree grew to a colossal size destroying the capital and barely sparing cities like Orsha and Fedimian. Then, monsters and demons started to attack the remaining survivors.
Why did this tree grow? What is this tree? Why monsters and demons have appeared? What are those tree root crystals?
I’ll try to awnser those questions.
But first, I need to explain what is mana in Tree of Savior.
THE CONCEPT OF MANA
Most of you may probably know that mana is that blue bar, which is used to cast spells or skills on RPG games.
In this game, though, mana is something more complex. Based on documents I found in ToS, mana is the life force, or a form of energy that composes the world and it spreads, like branches, around the world.
Mana can be used in many different ways. Zachariel used mana to animate the guardians on Royal Mausoleum and the magic barrier in Mage Tower was provided by Demon Lord Hauberk’s.
THE DIVINE TREE
“Long ago, during the time of creation when the divine and mortal dwelt as one, God created the sky where stars dance, the earth to support that sky, and all life. When he finished, he fell into eternal slumber, taking the form of a tree, the Divine Tree, wherein he would breath life force in and out to the world, completing the balance of life. He asked that no one would wake him from his sleep.”
Also known as “World Tree”, the Divine tree basically controls the flow of life force, or mana, to keep the balance of life.
MEDZIO DIENA
Giltinė, the Goddess of Death, for unknown reasons, turned the Divine Tree’s essence upon itself. By reversing the flow of life’s energy, the Divine Tree retakes the mana and grows to a tremendous scale, breaking the balance of life. In other words, the tree is “eating” the mana produced by itself.
TREE ROOT CRYSTAL, MONSTERS AND OWLS
Tree root crystals are not only a cheap stamina recovery feature, but it is also related to the Divine Tree.
The demons transformed parts of the Divine Tree to help them to consume spirits, and then create more monsters from the energy. To accelerate the process, demons manipulate the Owls, guiding the souls to the wrong path. Some demons even disguise themselves as goddess to deceive the souls.
That’s the reason why we have to kill onions (kepas) at the beggining of the game. They are onions which became cute monsters by absorving energy from Tree Root Crystals.
Note that the demons can rely on different methods to create monster. For example, Naktis, the Demon Lord of Curse from Great Cathedral, transformed pilgrims into monsters by manipulating their psychological weaknesses with a curse.
THE DEMONS
There’s another world beyond the world of Tree of Savior. Players who have already done Demon Prison may know something about it.
Medzio Diena, by breaking the balance of life force, opened dimensional cracks, allowing demons to freely cross between worlds. It probably also explains why Royal Mausoleum Worker’s Lodge is so creepy
FINAL THOUGHTS
Basically, Giltine is a genius. She hacked the most primitive essence of the world to bring caos to it. Congratulations Giltine.
REFERENCES
“The Understanding of Mana” - in-game document
“The Diary of Antares’ Investigation” - in-game document
“The Report of the High Barrier Magic” - in-game document
“Guardian of Zachariel’s Royal Mausoleum” - in-game document
“Mage Tower Revelation” & “Great Cathedral Revelation” - in-game document
Random NPC guy from Klaipeda
Article from Tree of Savior Wikia - http://treeofsavior.wikia.com/
talk about a bad sibling rivalry.