If you’ve been watching the Marvel Comics movies (judging by the box office numbers I would say that is most of you) then you noticed there is an underlying theme of different colored “things” with various powers. You will also notice Thanos tends to keep appearing. There is a reason for that.
Infinity or Soul Gems
In the comics there are six different gems each with their own special power. They were originally called Soul Gems, but were later renamed Infinity Gems. They are the Mind Gem, Time Gem, Reality Gem, Soul Gem, Power Gem, and Space Gem. Individually these gems are quite powerful. What Thanos figured out is that when they are all controlled by one person they are unstoppable.
The origin of the Infinity Gems is they were actually once part of the primordial entity, Nemesis. Many eons ago, Nemesis ended its existence rather than live as the only sentience in the universe. Nemesis shattered into pieces forming the six Infinity Gems.
Thanos and the Infinity Gems
(In the comics) Thanos was born on Saturn’s moon Titan. He is the child of Eternals Mentor and Sui-San. Thanos carries the Deviants gene which causes the physical appearance of the Eternals cousin race. His mother attempted to kill him at birth.
During his school years, Thanos was a pacifist and would only play with his brother Eros (Starfox) and pets. Growing up he became fascinated with nihilism and death. He worshiped and eventually fell in love with the physical embodiment of death, Mistress Death.
Thanos places all six Infinity Gems on his left glove to form the Infinity Gauntlet. Each Gem grants mastery over an aspect of the multiverse: Time, Space, Mind, Soul, Reality, and Power. When all six gems are combined on the Infinity Gauntlet it provides Omnipresence, Omniscience, and Omnipotence.
Thanos is desperate to win the love of Death. He offers her a token of his affection by completing a task she had given him. He promises to erase half the life in the universe.
The superheroes on Earth that were not killed band together to stop Thanos. To impress Death, Thanos allows the heroes a slight chance of winning. He easily defeats and kills nearly all of them.
Thanos also defeats and imprisons many of the universe’s cosmic entities including Galactus, the Stranger, the Titan Kronos, Epoch, Love and Hate, Master Order and Lord Chaos, and Eternity. The only entities with power greater than the Infinity Gauntlet are the Living Tribunal and the One-Above-All. After defeating Eternity, Thanos leaves his body and becomes the living embodiment of the universe. This leaves his abandoned body vulnerable to Nebula, his alleged granddaughter.
Nebula takes the Gauntlet off Thanos’ hand and wears it herself. She is able to undo all of Thanos’ actions. This restores her from disfigurement, brings the dead back to life, and reverses the damage done to the cosmos.
Another battle with the heroes and cosmic deities ends with Adam Warlock taking possession of the Gauntlet. Thanos appears to commit suicide. Warlock’s allies object when he plans to keep the gauntlet intact for himself, but he ignores them. Later it is discovered Thanos is working on a farm while contemplating his loss. Satisfied that he is no longer a threat, decide to leave him be.
Other Infinity Gem Collectors
Others have collected all the gems together for various reasons. The Elder wanted to use them to rid the universe of Galactus, The Man Beast used them to form the Infinity Thrall, and Loki was able to combine them with a sevent gem (Ego Gem). Even Galactus and the Grandmaster have gathered them all together. Several how tried to obtain all six gems such as Magus and Count Abyss.