Teenage Mutant Ninja Turtles
First appearance: Teenage Mutant Ninja Turtles #1 (May 1984)

If you've made it this far you are most likely a geek, so the Teenage Mutant Ninja Turtles need little introduction.  Four turtles mutated by radioactive ooze live in the New York underground surfacing only to fight crime and eat pizza.

Leonardo (Blue mask) - courageous leader of the group. Fights with two katana.
Raphael (Red mask) - wields a pair of sai, he is hot headed and aggressive.
Michelangelo (Orange mask) - fun loving, skateboarding, pizza eating. Fight with nunchucks.
Donatello (Purple mask) - inventor, scientist and tech genius. Fights with a Bo staff.

Wiki - Teenage Mutant Ninja Turtles

Lord Vringath Dregg was an insectoid crime lord who was the ruler of the planet Sectoid 1 and considers himself lord of all insect life in the universe.

Wiki - Vringath Dregg

Renet Tilley is a Time Traveller and Mistress of All time who wields the Sceptre of the Sands of Time. 

Renet was a teenage apprentice to Lord Simultaneous from whom she fled simply through boredom. Her adventure led her to befriend the Turtles.

Wiki - Renet

Armaggon is a mutant shark first appearing in Archie comics, but also appearing in TMNT comics and TV series.  In the 2012 TV Series Armaggon is a mutant Bount Hunter working for Lord Dregg.

Wiki - Armaggon