History
Chimu worked with Egros on the project to make their people survive their sun going nova by sealing them in stais chambers until the sun would hav cooled down enough. However, their calcilations were wrong and the sun went Nova ahead of time, causing the destruction of the whole race and fusing the human consciousness of Egros with tha of the planet, creating Ego, the living planet. Thor relived the last memories of Egros and Chimu when he entered Ego's mind[1]. However, it was later revealed tha all of this had been an illusion by Ego, so it is likely that neither Egros nor Chimu ever existed.