Cryptosporidium, known as Crypto for short, is the main character in the series. A member of an alien species known as Furons he is an anti-hero who enjoys wreaking havoc and destroying all humans. His name comes from the Cryptosporidium protist. Crypto's boss is Orthopox 13, who usually gives Crypto missions. Sometimes Crypto talks with a variety of wise-cracking remarks. He once notes that he is aiding a lot of humans, and says "Whatever happened to 'Destroying All Humans'?". Voiced by J. Grant Albrecht.
Cryptosporidium-136. - Often referred to as Crypto 137's brother, who is sent to Earth for a mission similar to 137's, collecting human brain stems. Unfortunately, Crypto 136 met an untimely end at the hands of human scientists: sacrificed and dissected in the name of science. Crypto is enraged when he discovers this, and his hatred for humans becomes personal. He presumably had the same personality as 137, as Crypto refers to him as 'me' sometimes (often confusing himself). Crypto-136 was the pilot of Furon scoutship sent by his boss Orthopox-13 find a planet that Furons visited many eons ago, a planet that was ripe with pure and more complete DNA. But while trying to land on Area-42 (Reference to Area-51), a missile hits his ship. His ship crashed and he was taken by the Military and Majestic for experimentation. Silhouette, the leader of Majestic-12, oversaw these events herself and was responsible for his death. He was later given an autopsy.
Cryptosporidium 137 - Wise-cracking, Jack Nicholson-esque protagonist of the first game. He has an unlimited amount of clones that will take his place if he dies during a mission, all of which have the same personality, but an increasing number appended to their name (Crypto 138, Crypto 139, and so on). He likes destroying things, and uses one-liners a lot. He was the successor of Crypto-136, created even when Crypto-136's fate was still unknown. Crypto-137 was the first Furon on Earth for over a million years. In chronological order, Crypto-137 had many notable accomplishments. He destroyed an army taskforce in an American mid-western farm, in Rockwell he destroyed the Annual Rockwell Fair, assassinated and posed (by Holobobbing) as the Mayor. In Santa Modesta he assassinated the Mayor, destroyed several population food controlled diners controlled by Majestic, killed Sleepy Ernst, then destroyed the Santa Modesta Majestic base. He discovered the fate of Crypto-136 in Area 42, he also blew up Area 42 with a nuclear weapon, as well as blew up the Area 42 Majestic Base with his saucer. He was shot down and captured in Union Town, but soon escaped and destroyed the Union Town Majestic Base. He later visited Capitol City, assassinated the President, he then returned to Union Town and posed as the Navy leader and stopped Silhouette's plan to lead all five divisions of National Defense. Just after that he destroyed General Armquist. He later destroyed Roboprez (the brain of President Huffman put in a 50 foot tall robot) and killed Silhouette. After that he permanently holobobbed the President and posed as him until his mysterious death between 1958 and 1969. Which Crypto-138, then continued to pose as the President. He was also the cause of thousands of human casualties, plus the death of several cows and chickens.
Cryptosporidium-138 - Was the President until 1969, when the mothership was destroyed by a KGB missile. His notable achievements include: Saving Bay City from a nuclear bomb, killing Coyote Bongwater, destroying 'the rock' (a KGB base). In Albion, he killed Oranchov, met Reginald Ponsonby-Smythe. He also met Natayla Ivanova, a former KGB agent. Later saves Albion from the deadly poison spores. Was betrayed by Ponsonby, but was rescued by Natayla, then killed Ponsonby. He then went to Takoshima where he destroyed both the evil black ninja and Japanese KGB base. He then saved Japan from Kojira (a summer intern at the KGB mutated into a Godzilla-esque creature). He then left to Tunguska, where he recovered info about Project Solaris, Destroyed a Blisk warship, and discovered a deadly secret, he then rescued Natayla, and flew to the moon, where he killed Milenkov, and saved the Earth from the infectious spores, just after Natyala gets shot in the back and is killed. Later, Crypto is lying around in his saucer with Natayla next to him, Pox says he's seen activity in the cloning pods, Crypto admits he made a few 'changes'. It is also noted that after he defeated the main Blisk Boss he completed an odd job to rid the moon of the remaining blisk survivors.
Cryptosporidium-??? - Little is known about this clone but he appears in multiplayer games as the second player. In the second game he wears a red suit, and in Big Willy Unleashed he just has a red arrow floating above his head.