There are lots of references to the term Indigo or Indigo Child on the internet, and they may present varying definitions and descriptions. However, I think of an Indigo as someone who has lived many, many lives on Earth over many centuries. These are the archetypical "old souls". Many have been preparing to incarnate on Earth at this time to help shift the planetary consciousness. They are here to use the knowledge that they have been cultivating on Earth over centuries to transform the planet. Indigos can have suffered a lot of trauma in past lives on Earth, and this trauma can and will have to be healed in this lifetime in order to proceed on the Ascension path. It is a mission, a blessing, and a burden to carry this trauma because Indigos can heal these energies from our history as well as themselves. Also, many Indigos may have lived in the times of Atlantis or Lemuria and thus have seen a time when the Law of One was observed on this planet.
Here are some possible characteristics....

• Easily recognizable as an "old soul"
• Born feeling and knowing they are special
• Confident as children and have a higher sense of self-worth
• Throws tantrums more often than other children
• Natural born leaders, and not likely to follow
• Does not respond well to authority, rules seem silly to them
• Can easily see the problems in systems that others take for granted, making them "system busters"
• Can feel misunderstood when not around other Indigos
• In touch with their personal needs
• Creative and artistic
• Interested in history, religion or other esoteric topics
• Prone to addictions due to voids left by past life truama
• Intuitive or psychic, multi-dimensional experiences from childhood
• Can be aggressive, introverted, over-emotional and moody
• Independent and self-sufficient 
• Have a big sense of their mission and wanting to profoundly help the world
• Extremely empathetic and sensitive
• Has a special connection to geographical places or eras in history that cannot be otherwise explained
• Prone to insomnia, restless sleep, nightmares, or difficulty/fear of falling asleep
• Connection to nature and universal love

Link to Indigo in Ascension Glossary

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