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(Source: Ch 10). The choice of who will climb is made by Headon, the Guardian of the 1st Floor. Regulars are chosen because they show potential like having a strong desire they wish to fulfill.

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 likely teleported immediately, to the Second Floor. (It is unknown if a grace period is given to them or if they're sent immediately to the Inner Tower.) 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).

Note #2: In the webtoon, the term used is actually "chosen regular". Grumpy simply shortened it to "regular". (Source: [])

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 2nd 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 or their Floor of origin in the Outer Tower or outside of the Tower after notifying the staff they've finished preparations and are ready to go back home.

When one becomes a chosen Regular and enters the Inner Tower, there is no rule that one must keep their outside name. In fact, most regulars use aliases when registering on either the 2nd Floor or on each Floor. (Source: Ch 29)

From the 2nd Floor to the 19th Floor, they get to sleep in dormitories as they aren't allowed to reside in the Middle Area.

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.

On the 20th Floor, they're chosen once again. Since 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.

From the 20th Floor onwards, 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.

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

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

Giving up their Regular status and their Rights
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. They can choose to live there, or move to a lower floor and live on with a new job (Source: Ch 79). Of course, depending on how far you've climbed, the way you're treated differs greatly. According to SIU, it's just like "climbing the corporate ladder". Source: [|here].

But if they belong to outside of the Tower and give up, they are probably teleported back home by Headon or the Guardian of the floor, if they don't want to remain in The Tower. Although it is also possible they aren't permitted to go home at all.

Note: It is unknown if Regulars from the 3rd to 19th Floors are permitted to reside in the Middle Area once they've given up, as they previously didn't have the right to do so. If such former Regulars aren't allowed to live there, then they're likely sent to the Middle Area so they can return home as it can be used to travel between the Inner and Outer Tower.

Ranking
All Regulars and even Rankers are issued a Ranking and Grading. Note: It is unknown for now, how this system works.

With the exception of a few(Androssi Zahard and Anak Zahard who were ranked 6E and 10E respectively in Part 1), majority of Regulars are F-Ranked Regulars when they first start out on the 2nd Floor. Once they've passed the 20th Floor, they become an E-Rank Regular.

Test points
Based on their performance and score during a test, Regulars earn a certain number of test points which are then used as currency. And these points can be used to purchase meals, drinks and so on. (Ch 31 and possibly Ch 55.

Although it's unspecified for now, at some point, they are also made to use these points to pay for taking tests. Or it is possible this practise is only enforced starting from the 20th Floor and onwards.