Basphomy seems to say that it's not as simple as the same soul being reincarnated in a new body, but souls are somehow derived from older souls so that souls have soul ancestors like bodies have genetic ancestors. Apparently a person's soul ancestors can be different from their genetic ancestors. Ozzid is bound to Quint's bloodline, his genetic descendants. The bloodline ended with Siphy Liberliganus, so Gwynn's body is not a genetic descendant of Alligia's body, but her soul is a soul descendant of Alligia's soul, according to Basphomy.

On the other hand, Gwynn's soul is apparently not descended from Queen Siphaniana's soul, as Basphomy says they're connected only because of the necklace.