108 Stars of Destiny (一百单八将)

The concept is a strong part of Water Margin.

The very first chapter opens with Grand Commander Hou disrespecting spirits by opening up a sealed tomb and unintentionally releasing 108 demons who presumably reincarnate as humans, a backstory to the events that follow years later.

This is well shown in the Japanese The Water Margin, but is skipped in the Chinese The Water Margin unfortunately.

The concept is also central to the Suikoden video game.

Actually, now that Ciro Santilli thinks about it, these were already likely meant as a "collectible" element by the author of the original book, as is strongly suggested by all the little illustrations of each character present on the Wikipedia page. Just like e.g. Catholic saints. It's Pokemon, but 2000 years earlier.

Ciro would notably feel many years later, that as he met random people online who were interested in improving eduction, or was otherwise networking to reach his goals, as if he were actually building up his 108 stars of destiny.

A central part, and perhaps the most interesting part of the novel, is how each character has been motivated by injustice to join the rebellion. This reminds Ciro of Final Fantasy VI