There are many Organizations in Mesmonia, both Human and Monster. Below are two of the most important Organizations for each, although there are many,these are the two you'll encounter throughout your normal adventure.
The R.D.U (Royal Duelists Unit)
Founded: 829 C.E
Founder: Zheru Ashtur (Female)
Location: Estellia, Mesia
These are a group of Female only Duelists. Their talents range from White and Red Magic to Sword Arts. Primarily used in the military of Estellia, they are also tasked with dealing with their rogue members. If you see a Duelist in the area, chances are they are looking for a rogue Duelist, and you should be careful in that area. They're easily identified by their typical "Duelist" outfits.
The Z.T.F (Zeretic Task Force)
Founded: Unknown
Founder: Believed to be Eternity herself
Location: Where they need to be.
The Zeretic Task Force is a group of Ancient Zeretics. As they are immortal as long as Eternity exists, they never age or speak a word. They're normally sent by Eternity or Zinn to keep an eye on certain people. While they naturally fear Succubi, they are never tasked to seek them out. They have ungodly powers, but are mere puppets on both the outside and inside. Though they can have a "free will",they normally follow the instructions they were built to follow. They're very easily recognized by their distinct lifeless eyes, and the heavy armor they wear.
The Dest (Monster)
Founded: Unknown
Founder: Unknown, however the monsters believe in their own deity.
Location: Everywhere.
Monster Family: Dragons(Head), Succubus(Head), Goblins, Seraphims(Scouts) Consumed Adventurers (Basically corrupted souls.)
The Dest are a very feared organization, which is made up of 4 major monster families (though Succubus's are considered human at times.), and a group of Adventurers promised a lavish lifestyle. The head of the Dest is Tamea, a Dragon. She is only ever seen or heard from when the Dest are making a movement against the humans. They aren't at war with the humans, but they do have conflicts at the towers of Mesmonia, which tend to be Tamea's Nesting grounds. The Succubus Co-leader, Roxelle, is believed to be the oldest Succubus still alive,and she's the one responsible for charming Adventurers, both male and female, to do her bidding. She commonly hangs out in major towns in the guise of a potion merchant.
False Zeretics
Founded: Unknown
Founder: Unknown
Location: Everywhere
Monster Family: Undead Adventurers
The False Zeretics are a group of adventurers who are, by definition, undead. To become a member of the False Zeretics, you have to undergo the Zeretic transformation, where a group of Succubi infuse their blood with yours, allowing you to ultimately mimic any ability a monster or player may use in battle. The average lifespan of a False Zeretic is 2 years after surgery,which is thought of as the "Trial Period". If you survive (by not succumbing to the insanity brought on by memories of the Succubi),you're a member. Despite leading a destructive lifestyle, the perks are immense,letting you wield any weapon, learn/use any magic, and even some monster abilities. After you've been killed off, which is inevitable, the group's Necromancer will raise you from your bloody grave, making you into his or her pet for the rest of your undead life.
The Sky Pirates
Founded: Unknown, but around the period of Airship manufacturing.
Founder: Ryan Ourgalles
Location: Skies over Mesmonia
Members: 20
The Sky Pirates are a group of pirates that utilizes stolen airships to carry out tasks for themselves or even as mercany work for king/queendoms.