In FF7, the chaotic life factor is implanted in Vincent, and some characteristics of the chaotic factor are similar to those of Genoa factor: it gradually devours the human body and evolves into a monster. Omega is the last letter of the Greek alphabet, representing the final meaning. Omega generally stands for research boss.
In the sequel Final Fantasy 7- Elegy of Cerberus, Omega is defined as "the soul born from the planet". After waking up, Omega will fly to the sea of stars with all the souls of life, and let the planet return to purity. Before that, we must kill all living things on this planet. Chaos is the carrier of Omega's boarding.
Therefore, in order to revive Omega, Baotiao slaughtered in DCFF7.