Regular

Definition
A Regular is someone who has been chosen from the Outer Tower to climb the Inner Tower. However, a few are also chosen from outside of the Tower The choice of who will climb is made by Headon, the Guardian of the 1st Floor. Regulars are chosen because they have a strong desire (please confirm) they wish to fulfill (money, women, beauty, strength, to avenge a friend's death, a promise they made to a friend, to see the stars, etc.).

The relationship between Regulars and non-Regulars is similar to that of the ruling class and the subjected class. This means that Regulars don't have to use any honorifics when addressing non-Regulars. And in turn, Regulars from the Ruling Class don't need to use any honorifics towards Regulars from common families. Source:Ch 32

Note: The key difference between Regulars and Irregulars is this. Regulars are chosen by Headon and then, instantly teleported to the Second Floor. However, Irregulars simply force open the door of the Tower and are then, teleported to the First Floor to take the Guardian's test (conducted by Headon).

Climbing the Floors and their Rights
The Regulars must take a series of Tests every time they climb a floor. And due to the difficulty and nature of the complex testing system on the Second Floor(Floor of Test), many fail there which means they are stripped of their rights. And the failed Regulars are likely teleported to a Floor in the Outer Tower or outside of the Tower after notifying the staff they've finished preparations and are ready to go back home.

From the 3rd Floor and on, it's a bit different. Even if they fail, the have the right to retake the test. Because the difficulty is not that high, they say that most of those who pass the Floor of Test also pass the rest. However, Regulars who give up in the middle of climbing the Inner Tower, after they've reached the 3rd Floor, are stripped of their rights and are sent to the Middle Area. This is likely so they can return home as it can be used to travel between the Inner and Outer Tower. However, Regulars who were chosen from outside the Tower are likely teleported back home by Headon or the Guardian of the floor or via some mechanism in the Tower.

From the 20th Floor, the right to reside in the Middle Area is granted, so while they dwell in the Middle Area by themselves or with their family, many also take the test after entering the Inner Tower. Taking a test requires a lot of points (money) and due to the increase in difficulty, they say there are a lot of Regulars who gave up on the 20th Floor. It's said that even if they've given up, their "premium" status as former regulars helps out a lot in their daily needs.

If a Regular reaches the 134th Floor of the Inner Tower, they become a Ranker.

If a Regular gives up while climbing the Tower, they can choose to live in the Middle Area, or move to a lower floor and live on with a new job. Of course, depending on how far you climb, the way you're treated differs greatly. According to SIU, it's just like "climbing the corporate ladder". Source: [|here].

Currently, many of the characters in the series are Regulars.