| Spoiler warning!|
This article contains plot details of Ys VIII: Lacrimosa of Dana.
Do not read it if you have not played the game and intend to play the game in the future.
The Lacrimosa is part of the Great Tree of Origins' evolution cycle. The Great Tree fosters evolution by means of selection and rejection: Periodically, the Great Tree causes an giant cataclysm, called the Lacrimosa, destroying most life forms in the world and altering it's environment. One species that can survive the environmental changes is chosen by the Great Tree to receive its blessings of evolution. This is necessary to sustain the worlds existence.
For every era ended by a Lacrimosa, one of the brightest souls is chosen to become a Warden of Evolution, an immortal being tasked with observing the earth and the evolution process.
Only two of the Lacrimosas are known. The Eternian Era was ended by a meteor shower. The Maiden of the Great Tree and the Queen of Eternia tried to protect Aegias, the capital of the Kingdom of Eternia with an Essence barrier but eventually the meteors broke through. With the meteors came a darkened ash-filled sky that rapidly lowered the temperature and destroyed the Eternians crops. The survivors of the impact began to die of diseases or hunger. Dana, this eras' Warden of Evolution, led the remaining survivors south in hopes of escaping the cold, but after a year she returned to the Great Tree as all Eternians were dead. She put herself to sleep to wait for Adol and help him stop the next Lacrimosa.
The following Lacrimosa was to be an invasion of Primordials, summoned by the Great Tree, overrunning the world. Adol, later marked to become the Warden of Evolution of this era, shipwrecked on the Isle of Seiren and, through an abnormal bond with Dana, managed to make his way to the Great Tree. The Lacrimosa had already begun and the Great Tree spawned increasing amounts of Primordials.
With help from the other castaways and Dana he managed to complete the plan of the other Wardens and obtain the power of the Tree of Psyches, which allowed him to enter the Great Tree's Selection Sphere and fight the Providence of Evolution. Defeating it awakened the Earth Goddess Maia, creator of the Great Tree.
As the world was Maia's dream, ending her dream ended the world. She reconstructed the world, with Dana becoming the Goddess of Evolution, replacing the Great Tree. Awakening Maia also meant temporarily stopping the Lacrimosa, but according to Maia it will return, and she entrusted it to Dana and the former Wardens of Evolution. They aim to use it as a tool to make the world a better place.