The Nexos took the place of Majestic and the KGB as the fourth Alert Level enemies. The Nexos first appeared in Las Paradiso, where they attempted to destroy Crypto and Orthopox and were later seen at the Sunnywood Stadium. The Nexo's technology was later encountered in Shen Long, and their source was located in Belleville. The Nexos were lastly spotted on the Fourth Ring of Furon, where the final confrontation took place.
There were three type of Nexos, who each appeared at different events, and different places:
Nexosporidium Warrior - Basic Nexos Infantry, there were three different types: Red the strongest, Blue the weakest, and Green, the common foot soldiers. The Nexos were armed with a powerful phase cannon in their right arm, used a small energy flail in close combat, and also fired rockets at their enemies. The Red Nexos were the largest of the three, were located around the Fourth Ring of Furon, and acted as law enforcement. Green and Blue Nexos were encountered during missions and when the Alert Level was Red.
Nexosporidium Saucers - Those were Saucers that were piloted by Nexos and were armed with twin energy cannons that resembled Crypto's plasma cannons to some degree. They served as the Nexo's air force and only attacked while Crypto piloted his Saucer. They once destroyed a human Military battalion in a battle for a lost relic.
- Sporidium may have been a run on word in Crypto's full name, Cryptosporidium. At one point, Crypto even made the statement: " Nexosporidium vs. Cryptosporidium".