*You don’t necessarily have to know all this to get into the RP, but here’s some useful info that might help you understand the setting a little
Regular: Someone who has been chosen to climb the Inner Tower by taking tests on every floor.
Ranker: A regular who has reached the top floor and numerically ranked on their performance. Rankers possesses immense fame and wealth along with overwhelming strength and skills they accumulated during their climb. The top 1% of rankers are referred to as High Rankers and are especially acknowledged.
Shinsoo: Shinsoo is a miraculous substance that flows through the Tower and each Floor has areas of varying amounts of Shinsoo density, increasing with each floor. In lower concentrations, its' density makes it act like a gas, but in higher concentrations, it's like liquid and restricts movement. It allows the residents of the tower to breath within the tower, and even creates an atmosphere within the tower that glows blue like the sky during the day and goes dark at night. Shinsoo can be controlled to be used in combat, regardless of one’s position, though Wave Controllers specialize in its use. Typically, interaction with Shinsoo causes people to stop aging at some point in their lives and grow physically in relation to the mind as opposed to age. As a result, age means nothing in the tower and people are judged by status and power instead; someone more than 300 years old could be beneath someone in their late teens.
Guardian: Guardians are powerful beings that are said to watch over each floor and test those who wish to continue upwards to see if they are worthy, though they currently delegate this duty to powerful rankers on each floor called Rulers and their administration rather than administer the tests themselves. The Guardian of the 1st Floor, Headon, is responsible for choosing regulars from around the tower and sending them to the 2nd floor to begin their journey up the tower.
Contracts: In the Inner and Outer Tower, if people wish to control Shinsoo without items (wands) they must have a contract with the Guardian of the floor. Items are only usable when it's under contract with the Guardian (For example, an item that is under contract with 2-30th floor Guardians cannot be used on the 31st floor.). It doesn't mean you cannot manipulate Shinsoo at all without a contract. Even when the contract is not made, some simple manipulation is possible. And the inborn resistance to Shinsoo or body augmentation/strengthening using Shinsoo is a power that exists naturally without a contract. The 10 Families and some other families can manipulate Shinsoo on any floor without special contracts. That doesn't mean they do not make contracts with the Guardians. They are 'under contract' the moment they are born.
Pocket: A spherical device that all regulars are given before entering the Inner Tower, which floats around the owner to avoid getting in the way and can be rendered invisible or visible with verbal commands. It serves as a universal translator and also includes a clock/timer function as well as a function that allows the regular to make contracts with guardians. The E-rank pocket regulars receive at first is only capable of storing contracts with guardians up to the 40th floor. Pockets
Lighthouse: A Lighthouse is a cube used for gathering information and emitting light, a necessity for teams since most battles in the tower are fought in the dark. It is powered by Shinsoo which exists everywhere so it is wireless. It also has wireless networking features which allows it to connect with external devices like another Lighthouse.
Arms Inventory: Similar to pockets except that they act as storage devices to hold weapons and other items for easy access in combat.
Wand: Items designed to allow someone to manipulate Shinsoo in certain ways through their use. They come in a variety of shapes and functions, though they must be contracted with a Guardian in order to work on every floor.
Outer Tower: The massive area where most residents of the Tower live their lives.
Inner Tower: A smaller area connected to the Outer Tower through the Middle Area where regulars collected from throughout the tower are sent to be tested and begin ascending.
Middle Area: The space connecting the Outer and Inner Towers. Regulars who have made it to the 20th floor but decided to not continue are allowed to settle in the Middle Area and there are pathways within it connecting the different floors though only Rankers are permitted to move through it freely. Residents of the Middle Area except members of certain families are not permitted to have children and those that are born are often sold into slavery or worse.
10 Great Families: The families founded by the 10 Great Warriors who helped the current ruler, Zahard, conquer the tower and are considered to be the nobility of the tower. Their members are often born with great power.
Zahard’s Princesses: Daughters of the 10 Great Families and certain other families who have displayed tremendous talent and beauty can be selected to become the king’s adopted daughters, essentially becoming the royalty of the tower. In the process, they are given the King’s strength and become exceptionally strong. Being recognized as a Princess is an honorable and almost impossible achievement and there are many candidates vying for the position, with one being selected only every several hundred years.