Avatar is the third phase of combatuid evolution. When the pilot/summoner eventually reaches the soulmend, he/she realizes that it is not the body who he/she is, but the very soul itself. Everything material is the form of a thought, including thee body. Therefore the body can be enhanced into a new form that is an avatar of the soul. It can be anything. The pilot does not don the combatuid any more, but becomes itself in a material form.
Only very few characters could achieve this ultimate form: