In my universe there is a race of proto-humans known as legionaries. They have a are a minority group and used to be even smaller, only living on one planet in the past. This race used to give birth to litters of 7 children when they bred. However, after a mad scientist released a biological agent into their most prominent water supplies he was able to force their race to mutate and the next generation of this race were the first generation of 'true' legionaries. This new generation did not come out as litters but instead, gave birth to one child with seven fully developed and realised personalities that show prominence at different times.
Since then the previous litter bearing generation has died out and all that remains are legionaries integrating with the rest of society. Aside from the multiple personalities inhabiting the same body at the same time, they have one other biological difference from humans. These proto-humans will rapidly change their body depending on what personality is currently in control. Certain personalities are taller than others, have more muscle mass than others. these changes are not so drastic as to make the new body non-distinguishable from the original, but would instead have the same resemblance a sibling may have. The race is agender as the most drastic change a legionaries can have between personalities is their biological sex itself.
In this question I ask what implications would a race like this have on the rest of society, would much change? What would change as a result? And what would be the likely reaction from other people as a result of these legionaries?