Humans
It's amazing how humanity can still persevere even as one of the most frail species. Humans look like... well... Humans. Their ability to adapt is their greatest strength. Most Humans are either warriors, druids, merchants, or some kind of royalty, and have an extreme hatred of those who wield the Remnants. Humans often forsake the history of the world, believing it to be a vile past, and that the future is what the races should think about.
Racial Bonus: Adaptable
Humans have no innate advantages, but also lack any disadvantages. They're essentially the baseline between all other species.
Elves
The fair Elves are frail and tall, and possess tapered ears. Elves have powerful pheromones, which are difficult to resist for a sentient being, and impossible to resist for an animal. Most Elves don't use Remnants, although they enjoy studying them. Elves are keepers of history, but only history of the events after the Great Cataclysm, as the records of beforehand were long since destroyed.
Racial Bonus: Enchanted "Beauty"
Thanks to powerful pheromones, Elves get a natural +2 to the Persuasion, Seduction, and Intimidate attributes, enabling them to raise these skills beyond a 10. They may also perform Persuasion and Seduction rolls on animals.
However, Elves are frail and not fit for combat, giving them a -1 to all Physical stats.
Dwarves
The Dwarves are a reclusive species of short and stout miners, with the ability to operate with little air, and smell any metal from a short bit away. The Dwarves possess many Remnants, but know little about their workings. Dwarves have a strange affinity for the Giant Wasp Canary, probably dating back to before the Great Cataclysm. Dwarves are keepers of history, and know a lot about many events, including those that predate the Great Cataclysm.
Racial Bonus: Tinkerer
Natural born tinkerers, Dwarves begin with 3 points in Crafting (note: this is not the same as a +3).
Being short doesn't mean they're durable, though, and therefore decreases their starting hit-points by 20.
Demons
A reptilian species with horns and gills. They only have three digits on both their hands, and feet. Although not evil, Demons tend to shun outsiders, and stay near their underwater Leylines for heat. Demons are not harmed by Cataclysmic Energies due to their scales, and as such are safe near the Leylines. Demons also can breathe underwater. Demons tend to enjoy the power that Remnants grant them, but usually fall to power's sweet embrace. Demons don't really care about history of other races, although they never forget a moment of Demon history.
Racial Bonus: Survivable
Due to the harsh environment and predation, Demons have developed water-breathing gills, immunity to Cayaclysmic Energies, and sharp claws.
Their claws give them a +2 to Unarmed.
The social prejudices regarding Demons make them unable to raise their Appearance or Charisma stats past 2, and restricts them from certain shops or areas.
The Decay
The Decay are normal humans save for one thing: they constantly rot. The Decay rot because their bodies survived Cataclysmic Energies and destroyed the cancers that came about because of them, however, their bodies couldn't tell the difference between the cancers and the healthy flesh, and began destroying the healthy flesh. The only way for one of The Decay to survive for longer than a decade, is to eat the flesh of another being, usually a sentient being, as these have the nutrients to repairs their bodies fast enough to keep the rot away, however it doesn't last long, and eventually they start decaying again. The Decay pay little attention to Remnants or history, having to live in the moment to survive. The Decay are rare to see, and often misunderstood as "zombies". The Decay's condition cannot be spread without Cataclysmic Energy.
Racial Bonus: Regeneration
Paradoxically, the Decay can heal incapacitating injuries thanks to an accelerated metabolism. Though it does little to stop the rotting (and might actually be the source of it), it enables them to heal 1d10 of hit-points per turn without the need to rest or self-medicate.
However, your decayed flesh means you can never raise your Appearance stat and are unable to use the Seduction attribute.