Fixten
Have you ever seen in media when 2 people fuse temporarily by turning their bodies into energy and recombining? The result is a powered up being with 2 consciousness, and with the twins compatibility, will be stronger. The 'Return to 1 fetus'. Otherwise, the other direction of forming a new 'sibling' to unlock more battle formations and possible specialties (not truly living, temporary beings!!!). How this siblings consciousness is formed is up to them, may it be an ai chip or giving it specific parts of their own personalities. The 'triplets, quadruplets ...'