What characters are; their heritage and biology (or robotic specifications).
A character’s genus - genera being the plural - is the overarching umbrella of what they are, comparable to race in other games.
It is the classification by which they’re most likely to be referred, and provides one or more traits common to all species, as well as possibly an inherent stat boost.
Their species is the more specific thing of what they are, comparable to subrace in other games.
A character’s species contributes additional traits, potentially affects specifics such as appearance, and provides an inherent stat boost if their genus didn’t already give one.
Despite artificial lifeforms such as robots not being ‘genera’ or ‘species’ in the traditional sense, these terms were invented long before the creation of self-replicating AI… Sometimes terminology has to move with the times.
Every character will get a starting boost to one or more stats, derived from either their genus or their species.
These boosts - usually giving a total of +3 across any adjusted stats - bridge the gap between genus identity and player flexibility.
The stat boost, listed in the information for each genus or species, could say that one of the boosted stats must be the stat most thematically-related to that creature.
For example: The Kraken, known widely for their impressive intellects, get a +2 and a +1 to different stats. One of these two boosted stats must be Intelligence. The other can be anything you want that is not Intelligence. A player who plans to build an Intelligence-based Kraken would likely choose to use the +2 for INT; they would then have to use the +1 for a different stat, such as FIN. Alternately a player wants to make a dimwitted but strong Kraken, so they use the +2 for MGT; they must then use the +1 for INT to satisfy the genera requirements. Essentially the inherent brainpower of the Kraken shines through in some form, even if it’s not the priority.