What is the purpose of the Human Instrumentality Project? The Human Instrumentality Project is one of the main plotlines in the Neon Genesis Evangelion original series. However, other than a few speculative mentions, there isn't concrete information as to what purpose it serves. 

What purpose does the Human Instrumentality Project serve, why is it necessary, and what part does it plays against the Angels (if any)?
The ultimate goal is to unite all the individual souls of mankind into one singular being.

This would create an existence where nobody existed individually, but as part of a whole. 

This way, the flaws in every living being would be complemented by the strengths in others, thus erasing the insecurities in people's hearts. Creating the ultimate, god-like being.

To achieve Instrumentality, the merging of Adam and Lilith, resulting in the Third Impact, is required.

Both Seele and Gendo had their own idea of instrumentality. Neither was realized.