Given the fact that the 108 Stars of Destiny is one of the key concepts that were borrowed from Shui Hu Zhuan as a defining element in the series, the games rarely discuss them. All I remember was Fukien making references to them, but later on all we got are Leknaat's canon ending speeches and even then they are only referred to collectively, not individually.
...apart from one being born naturally under a specific Star (similar to how Zodiac works) and it remains the same for that person for the rest of their lives, that is. And, how some characters who change sides between games gain and/or lose their spot on the Tablet of Promise, e.g. Leon Silverberg, Lucia, etc.
However, it's worth noting that "becoming Starbearers" in Tierkreis is more about becoming able to access and use the Mark of the Stars. Maybe these people have always been born under these stars, it's just that their active contribution as an ally in the war doesn't begin until they experience the mind-shifting event. You know, how it is rumoured that Ace was actually part of Gilbert's mercenaries and thus was part of the Dunan Allied Army, but wasn't recognised as a star then, but did become one during the Second Fire Bringer War.
(More intriguing are the introduction of souls representing specific Stars, like Belemuel and Enumclaw.)
Aren't Shui Hu Zhuan's 108 supposedly represent some kind of demons anyway...?