After suffering three defeats at the hands of Spider-Man, Doctor Octopus realized that he needed help against the web-slinger. He got in touch with every superpowered villain who had battled the wall-crawler.In the end, five other super-criminals heeded Ock's call---the Vulture, Electro,Kraven the Hunter, Mysterio, and the Sandman. However, Doctor Octopus recognized that he would never be able to control these super-villains. They were incapable of working together or functioning as a well-oiled machine. Instead of trying to change this unruly bunch, Doctor Octopus conceived a battle plan that exploited their individual appetites for personal glory. Each member of the Sinister Six would stage a separate battle with Spider-Man at a carefully chosen location. One by one the criminals would fight him until the wall-crawler was finally destroyed.

Members

1st line-up

Doctor Octopus

Electro

Kraven the Hunter

Mysterio

Sandman

Vulture

2nd line-up

Doctor Octopus

Electro

Hobgoblin

Mysterio

Sandman

Vulture

3rd line-up

Doctor Octopus

Electro

Gog

Hobgoblin

Mysterio

Vulture

Hobgoblin's Sinister Seven

Beetle

Electro

Hobgoblin

Mysterio

Scorpia

Shocker

Vulture

Sandman's Sinister Six

Electro

Kraven the Hunter (Alyosha Kravinoff)

Mysterio (Daniel Beckhart)

Sandman

Vulture

Venom

Sinister Twelve

Boomerang

Chameleon

Electro

Green Goblin

Hammerhead

Hydro-Man

Lizard

Sandman

Shocker

Tombstone

Vulture

Venom (Mac Gargan)

Civil War Sinister Six

Doctor Octopus

Grim Reaper

Lizard

Shocker

Trapster

Vulture

Alternate Versions

Age of Apocalypse (Earth-295)

Mr. Sinister formed a faction named after himself, although this faction is not related to the group of Spider-Man villains. It is made out of Cloak, Dagger, Siryn (named Sonique in this reality), Sauron, Blob, and Jean Grey in the Dark Phoenix persona.

Marvel Zombiverse (Earth-2149)

A zombified version of the Sinister Six has seen attacking Wolverine and Magneto, who were protecting uninfected people taking shelter in a SHIELD Helicarrier.

MC2 (Earth-982)

In this alternate future, the group is now called the "Savage Six", which is composed of Dragon King, Funny Face, Killerwatt, Mr. Abnormal, Raptor and Sabreclaw.

Ultimate Universe (Earth-1610)

In the Ultimate Universe, the group is called the Ultimate Six. They are composed of Doc Ock, Green Goblin, Electro, Kraven the Hunter, Sandman and Spider-Man, who was forced to be a member and leader. They fought Nick Fury and his Ultimates where they were defeated with the help of Spider-Man. Peter was force to join the group because her Aunt May was thought to be kidnapped by Norman, but was informed by Captain America that she is safe in SHIELD custody.

Spider-Man: Reign

In this reality, the group is now called the Sinner Six. They are made out of Scorpion, Kraven the Hunter, Electro, Hydro-Man and Sandman. They were formed by Mayor Waters, and if they kill a recently appeared Spider-Man, they will gain their freedom from the sealed-city of New York.