Z Gang

The Z Gang is a notorious gang of misfits and thieves that is on the Order of the Knights' most wanted list. Crimes include, but are not limited to: They are apparently versed in Aegye and were planning to conquer the world.
 * causing a riot in Geffen by spreading rumors about ghosts
 * poisoning the drinking water in the wells of Payon
 * seizing countless goods
 * profiting off illegal trade

Louis Von Silokens
Louis Von Silokens is the third son of the noble Silokens family, which was ruined many years ago. According to record, he failed the Magic Academy three times. It is believed that he formed the Z Gang as a result of his personal failure and is thus the leader of the gang.

Martha Hertizen
Martha Hertizen is the second daughter of Alberta's Hertizen family. No one knows why she ran away from home at the age of twenty. She is a talented Merchant who handles the Z Gang's finances.

Catfoii
Catfoii was thought to be Louis and Martha's pet cat, but is actually a master criminal with the ability to talk.

Hideout
The Z Gang's hideout was originally located in the basement of the Kafra Corporation western division's headquarters in Comodo. The hideout contained a special safe that can only be unlocked by activating 2 hidden switches. After the Rogue Guild began hunting them down, the gang fled.

They later move underground somewhere in the Sograt Desert. As a measure of defense, the hideout is outfitted with a system that sends out waves of monsters to decimate any intruders and cloaks the gang in invisibility with the push of a few buttons.

Story
"Spoiler warning: Plot and/or ending details follow." One day, the Z Gang commits a crime that involved stealing the Diamond of Ruin from a man name Ibrahim at the Morocc ruins. They store the diamond in their special safe within the Kafra building in Comodo only to have to flee without it when they discover the Rogue Guild was coming after them.

They later steal the Forbidden Secret Art book from the Prontera library. This put the Rune-Midgarts Kingdom on high alert, as the contents of the book could bring devastation upon the kingdom. Eventually, the National Wanted Notices that were posted all over Prontera caught the attention of a passing adventurer that decided to take on the task of capturing the Z Gang. In time, the Z Gang caught wind of the adventurer's activity, prompting Catfoii to enlist the aid of an informant to kill the adventurer. Little did they know that the adventurer was much stronger than they thought.

In the meantime, the Rogue Guild was hot on the Z Gang's trail, putting them even more on edge. They've since remained in the security of their underground hideout in the Sograt Desert.

It wasn't long before the adventurer discovered their secret hideout and infiltrated it. When the adventurer clears out the first wave of monsters, Louis tries to send out the second wave. Unfortunately, he presses the button that uncloaked him and the others instead of the one that would unleash the second wave of monsters. Now revealed, the adventurer warns them to surrender lest they face Prontera's Order of the Knights. When Louis and the others refuse to surrender, the adventurer changes tactics and says that they will face the wrath of the Rogue Guild instead. Faced with bleak prospects no matter what, Louis and the others surrender to the adventurer and hands over the Forbidden Secret Art book to the adventurer. As a courtesy, since there was no point in continuing to be bad, Louis commands Catfoii to show the adventurer the way out of their hideout.

Trivia

 * The Z Gang seems to be a reference to Team Rocket from the Pokémon anime.