World
As collected from information provided by the comic up until this point. Except for the Kingdoms part, because it's a bit bland and related more to the overall world than the plot.

BASIC PREMISE

Zaen Well takes place on a continent called "The Four Kingdoms" (yes, very original; the politicians weren't feeling very grand that day), specifically taking place in the kingdom of Tenro.

In this world, magic exists. However, this magic manifests itself differently in each kingdom, producing four different types of magicians that, previous to the Peace treaty, were often used against each other in combat. The magicians of Tenro are known as Harpers. Since Zaen Well doesn't actually focus on international and intermagical conflict, the other three magician types will likely not come up.

(For funsies, though, the magicians of Mizuia are called Eyes, after the four eyes of Mizuia's founding goddess. Harpers interact with Eyes the most out of the other three magician types).

HARPERS

Zaen Well mostly centers around how one becomes a Harper. Students identified as magical attend the Harper Academy in order to become certified as an official Harper. Students also seem to choose a major to become different types of harpers (as of now, the only two majors known are Healing Majors and Attack Majors).
As part of their training, Students must undergo a "journey" through Zaen Well in order to bond with a God. This bonding is critical to the student's future career as a harper, and is unique to Tenro Magicians. However, journeying through the well itself is dangerous.

A harper has been described as having extra "sight", which allows them to see ghosts, spirits and other creatures that normal humans cannot see. They also seem to channel their magic primarily through music of some sort.

ZAEN WELL

There is a "tear" between the Gods World and Human World at the bottom of Zaen Well. Harpers can navigate their way through this tear and into the God's world, allowing them to proceed on their mandatory journey to find a God to bond with.

Every student must follow three rules:

1) Do not stay in the well for more than a fortnight (14 days)
2) Do not speak of what happens within the well when you return
3) Do not let go of the chain

Renee mentions how a student who lets go of the chain is unable to return to the human's world, and may in fact wander about eternally. However, not much is exactly known of what happens to a student who lets go of the chain. It has been shown recently that some gods have the ability to transform and enslave students unfortunate enough to have not returned to the human world.

RUMETH HARPERS

As of now, the Rumeth Harpers are pretty much a mystery. They are named as a special clan of Harpers that seem different even from normal Harpers. Something about them immediately alerts gods to the fact that Renee is one.

(And for the record, Seth and his entire family are also Rumeth Harpers)

"Rumeth" is said to be the God that guards Rumeth Hill and, consequently, its harpers.


content (c) sonia liao