[quote=@Yatagarasu]
<Snipped quote by Legend>

*Smiles* 
Now we're on the same track. If it's not biological in nature, then it probably has a metaphysical component. So if you add that to the equation, what ideas come to mind as possibilities? And for the record, yes, we've been able to detect something similar to a soul in all four of you kids, but that's a conversation that can wait for another time.
[/quote]

Shion could always have multiple souls. If your bodies were barely compatible, maybe your souls weren’t. Or the souls could have come from somewhere else.