Icolo (イコロ) is a guild made up of the three Arena Emperors. It was originally founded by Antares as a place reserved for the most powerful Arena fighters. However Antares grew disillusioned when he discovered that the other Emperors valued their titles and the status it gave them more than their comrades or improving their skills. Leaving the Guild he gave his title of Guildmaster over to Taihaku, who still rules over the guild to this day.
Icolo's @Home is located in Lumina Cloth. It is a quiet place, filled with marble pillars and dark tapestries. A citadel for the champions of the arena to meditate on their upcoming battles, the @HOME itself is overseen by King Grunty, who only allows strong players to enter.
Eager to prove his own strength, Taihaku entered the supposedly unbeatable Forest of Pain event solo. His successful completion of the event increased his fame, and helped spread Icolo and Taihaku's names throughout The World R:2. This drew Phyllo to the guild, looking for information on Haseo, who was still inside the event.
After winning the title of Demon Palace Emperor, Alkaid was accepted into Icolo. However after Endrance succeeded in defeating her, she lost her title and her place within the guild. Angry over her loss, Alkaid swore to defeat Endrance by any means necessary and regain both her title and her honor.
With help from Icolo's former Guildmaster Antares, Haseo entered into each of the three Palace Tournaments and succeeded in defeating their Emperors. With assistance from both Antares and Alkaid, Haseo was able to knock Sirius and Taihaku out of their stupor, and begin the long process of restoring Icolo's honor. Now titleless, the Emperors would have to relearn what it meant to be Arena fighters. As the new Sage Palace Emperor, Haseo was supposed to receive the title of Icolo's guildmaster, but he declined the position, saying that he wanted to concentrate on Canard.
- The members of Icolo are all named after stars.