Dethklok fans (also known as "DethFans") are people who love Dethklok & their music to the point of fanatical obsession. Most fans are easily influnced by Dethklok to the point some have accidently killed themselves as a result of following the lyrics of one Dethklok's songs (Go into the Water).
Pain Waivers are a perfect example of how far fans are willing to go to see Dethklok (removing Dethklok from any & all liability).
Dethklok's music has been shown to have an almost hypnotic effect on certain people causing most people to become instant fans (such as producer Dick "Magic Ears" Knubbler). It is because of this that most of the world's population are rabid Dethklok fans. This effect was used by the Revengencers, who used Dethklok music to brainwash fans and create an army.
Most Dethklok fans are extremely loyal to Dethklok to the point some are willing to die to protect them. Some are so fanatically devoted to Dethklok that they apply to become Klokateers.
However the fans love & devotion of Dethklok is one-sided, as the members of Dethklok hate & despise their fans (the Fansong is a perfect example of how Dethklok feels about their fans) as they are often mentally unstable, disturbed or just stupid. In "Dethdoubles", Dethklok constantly refers to their fans as "douchebags", and often makes jokes about them, calling them "regular jackoffs".
However some fans like the Jomfru brothers have shown to have opposed Dethklok, despite being fans. This started to become more prevalent during season four when fans actively booed the band when they held a free concert after Nathan caused a global recession.
They also seem to realize that they have the power over Dethkloks popularity. During "The Fans are Chatting" they even used the Jomfru brothers mantra of "We're the power, We're the fans". When Toki was kidnapped the fans noticed he was not seen in public with the rest of the band and demanded answers. Ultimately it was the fans leaving a Dethklok concert that finally convinced them to go and save their band mate.