Evil Evil Evil Evil Evil Evil Guy is a hater you do not want to see, get involved with, or even hear about! He is 6 times as evil as Evil Guy, and that is a lot of evil. It is a good thing that he was killed by Deidara, or we would all be dead! Sadly, he has been revived. Not by the Revival Machine, but by Bob Saget. Now, he is a ruthless undead that wants to pwn everyone! It's a good thing though that the Evil Guy Family is nearly destroyed.
Evil Evil Evil Evil Evil Evil Guy (or Evil Guy x6, as I shall abbreviate his name from now on) has barely been seen by anyone and is therefore shrouded in mystery. He is secretly the boss of the Shy Guy Armada, an organization that houses the entire Evil Guy Family.
Evil Guy x6 was murdered in his sleep by Deidara, who committed this crime in cold blood. The only reason that Deidara was able to track down Evil Guy x6 is that he is, in fact, a ninja and is therefore a master of stealth, which is an absolute necessity if one should attempt to sneak into Evil Guy x6's secret base underneath Yoshi's Island.
After his death, Evil Guy x6 was sent to Hell. There, he met Bob Saget, AKA The Devil, whose heart contains the maximum amount of evil that Hell can hold. Since Evil Guy x6 exceeded this amount of evil, he could not be contained by Hell and was promptly released into the waking world once more by Bob Saget himself.
Currently, Evil Guy x6 has gone into hiding once more. He appears in the movie EvilGuy 008 as an antagonist, where Evil Guy hunts him down after being betrayed by the Shy Guy Armada. Whether Evil Guy kills him or not will remain undisclosed to prevent spoilers. For more information, check out the EvilGuy 008 article.