Individual identity is not fixed -- neither is group identity.
Individual Identity is acted upon by people, experiences, traditions, mass media, institutions, ideas and more. Identity evolves through the assimilation of these actors into its framework. Societies evolve similarly on a larger scale.
Each of us wears many masks in our lives. We choose which masks to wear at which moments and we make alterations to each mask as we learn. The collaboration of all these masks forms our identity. We can direct this process through conscious and unconscious decisions based on principles we have selected and developed for ourselves.
The construction of idealized identities or avatars can also inform our own identity by reflection. You can become your personal guardian angel and see the whole of your timeline at once. The trick is to tell a number of tales that seem disconnected when in fact, the tales all concern the same person under different disguises, or even a group of people under one disguise - something approaching corporate personhood.
By our conscious intent, we begin to forge our own identities in accordance with the very best we can imagine ourselves to be. We redefine identity to expand our potential, and we tell stories that reflect this process.
We can destroy the ideas that create excessive power and free ourselves from their terrible grasp.
For instance, the belief that every matter can only be resolved by a fight for dominance between opposing sides is constantly reinforced in our society to support the state apparatus that creates this belief. It's only our belief in this narrative which makes it come true, however. We can change the narratives that bring our societies only pain and misery.