Taneleer Tivan is one of the Elders of the Universe and is close to his fellow Elder En Dwi Gast (the Grandmaster). He apparently came to self-awareness billions of years ago, on the planet Cygnus X-1. He is an enormously powerful being who wielded the Power Primordial and, though at first he took the appearance of an old human, his true form is a powerful alien.
For millions of years, the Collector lived on an unknown world with his wife and child, spending his days in thought and contemplation. Over three billion years ago, when his wife, Matani Tivan, lost the will to live and relinquished her immortality, the Collector realized he would need a hobby to maintain his own sanity, and began collecting interesting artifacts and life forms from around the universe. Eventually, his obsession reached such heights he collected anything he considered rare or valuable often just for the sake of collecting. As such, he has a wide variety of rare or unique items at his disposal.
The Collector also had the power of prophecy, allowing him to foresee the rise of a being powerful enough to pose a threat to the Elders: Thanos. To protect life in the universe, the Collector created a massive museum of countless life forms to keep them safe from Thanos. For a time, he even possessed one of the six Infinity Gems, unaware of its true power, until Thanos took it.