The races still consist of dwarf, elf, half-elf, halfling and human. Use the normal Racial Traits and then the Cerilian subraces as shown below. The other subraces should not be used. Humans will use the Variant Human Traits rule based off of their culture; Anuirean, Brecht, Khinasi, Rjurik, or Vos.
While they are not part of the original rules, there should be no problem including gnomes (forest subrace) as a playable race. They are part of the setting, though not specifically as a player race; ask you DM if they are allowed.
It is not recommended allowing half-orcs, tieflings or dragonborn. They were never in the original rules, not even as monsters.
Born to the mountains, and through constantly fighting the orogs, you have become like the stone you live beneath. This hardiness has given you a dense body, weighing twice that of a human of the same age despite being under 5'.
Ability Score Increase. Your Strength score increases by 1.
Dense Body. Bludgeoning or crushing attacks that you take from non-magical weapons is reduced by 3.
Calling yourselves the Sidhelien, you are reclusive and stay within the remaining woodlands of Cerilia. The woods are your home and none can equal you within their leafy folds. As tall as a human, you are slender and graceful, possessing an unearthly beauty.
Ability Score Increase. Your Intelligence score increases by 1.
Nature Walk. You may cast pass without trace once a day, but only on yourself.
Despite being born of elf and human parents, you are accepted within elven society. Humans on the other hand are distrustful of any sort of elf, including half-elves.
Use the half-elf as found in the rules. There is no need to make any changes.
Originating in the Shadow World, the halflings were forced to flee that realm and now make their homes among the Big Folk. You blend in well with humans, adopting the culture of whoever you are near.
Ability Score Increase. Your Wisdom score increases by 1.
Shadow Magic: You may cast detect evil or good once a day. When you reach 5th level, you can cast dimension door once per day. Wisdom is your spellcasting ability for these spells.
You are the most populous race in Cerilia, spread throughout every corner of the continent. Five main cultures exist and help define national regions; Anuireans, Brechts, Khinasi, Rjurik and Vos.
Use the Variant Human Traits rule instead of subraces for humans. The only difference is that one of the two ability increases must be from the list below.
Anuirean +1 Wisdom
Brecht +1 Dexterity
Khinasi +1 Intelligence
Rjurik +1 Constitution
Vos +1 Strength