Koinonian (physical being)

The Koinonians were an ancient intelligent culture that was composed of two different lifeforms. One of energy and the other of matter. The physical ones destroyed their civilization a millenia ago, after several generations of war. They left ruins that were studied by an Enterprise-D away team in 2366. The energy Koinonians had strong morals and protected Jeremy Aster after his mother was killed by an ancient weapon. (TNG: "The Bonding")