FUG

F.U.G (퍼그/FUG, Peogeu) is the most dangerous and secretive criminal group in The Tower lead by Grace Mirchea Luslec. Their official members explicitly (though not all the time) wear the "Mark of the Slayer". .

FUG is often compared to the Walhaiksong because of their opposition to the 10 Families. However, whereas the Walhaiksong is more of a "social club" centered around several members, FUG is a "religious organization" centered around a single faith: to kill Zahard and the heads of the 10 Great Families. Although the relationship between the two organizations are not that good, there are a few members who are associated with both groups.

Although FUG’s true motives and goals are not clearly known, it is true without a doubt that they exist in the shadows of the Tower, hoping to acomplish their objectives.

The 10 Families forbid anyone within their Families to enter FUG, and they consider it an important duty to eliminate their members, who are known to hide within the shadows of the Middle Area. Despite its dangerous status, it does not mean that they hold enough influence to challenge Zahard and the 10 Families. As long as Zahard and the 10 Family Heads hold the contracts given by the Tower’s Guardians, FUG’s influence cannot overcome the Family Heads. In order to bypass such matter, the organization awaited a long time for someone free from the Guardian’s Contracts: an irregular (such as Jyu Viole Grace ) or a power source (such as Enryu's Thorn) not bound by the contract and incorporate them to their ranks.

Slayers
Within their infrastructure, FUG has 11 Slayers (슬레이어, Seulaeiyeo). The origin of the name is very simple: "One who kills" Zahard and the 10 Families.

There are presently 7 Slayers active: 5 have unknown whereabouts; 2 are acclaimed as "devils", and the remaining 4 positions are vacant. All of them supposedly very powerful.

"In FUG, there are those who have a grudge against 10 Families and Zahard, those who envy what they possess, and those who want to change the tower. A Slayer is a GOD who fulfills their wishes." (Ch 116)

​According to  SIU: Slayers are treated as walking Gods by FUG members.

Organization Information
FUG is an organization and not an organization at the same time. They are a group, so they can be called an organization. They have no physical forms or headquarters (unlike an organization), but membership is bound very strongly. Similar to religious faith, membership of FUG is embedded deep within its members hearts and wherever they walk or stay becomes a headquarter of FUG.

Structure
FUG itself has no structure. They are simply FUG, and they act upon their faith in the Slayers. The countless groups that operate under FUG simply work toward their given goals and do not associate directly with FUG. All Slayers, however, are united under the ultimate goal of Zahard's death. FUG members can seemingly make an "espionage" happen in order to attain seats of authority regarding Regulars on different Floors, as more than one FUG member is a Test Director.

Though this can leads to many problems, since their is no real structure groups can go against ideals of others. Like when some members didn't like the idea of giving Baam the thorn, so they conducted their own plan to take it for themselves.

Slayers

 * Grace Mirchea Luslec: Founder and No. 1 Slayer of FUG.
 * Karaka: Slayer.
 * Imort(e): Slayer.
 * Baylord Yama: No. 7 Slayer of FUG

Others

 * Ha Jinsung: High Ranker, Viole's martial arts teacher. Also taught Karaka.
 * Jyu Viole Grace: Slayer Candidate.
 * Hwa Ryun: Guide
 * Augusgus: Test Director of the 20th Floor
 * Yu Han Sung: Test Director of the 2nd Floor

Affiliated With F.U.G

 * Kang Horyang (Viole's Team)
 * Novick (Viole's Team)
 * Ran (Viole's Team)
 * Reflejo (Viole's Team)
 * Yuto (Viole's Team)
 * Beniamino Cassano (Viole's Team)
 * Xia Xia (Viole's Team)
 * Varagarv (Team Mad Dog)
 * Ron Mei (Team Mad Dog)
 * Viviolga  (Team Mad Dog)
 * Ridong (Team Mad Dog)
 * Pandit (Team Mad Dog)
 * Grobin (Team Mad Dog)
 * Apple (Attempted murder of Koon Aguero Agnis)
 * Rachel (Attempted murder of Koon Aguero Agnis)
 * Michael (Attempted murder of Koon Aguero Agnis)
 * Miya
 * Devil Bon

Possible Affiliations to F.U.G
Note: Some characters may be listed here if it's unclear whether they're related to FUG.
 * Madorako: A business working as a financial consultor for Gong Bang's research proyects involving Living Ignition Weapons

F.U.G