The Cerilian dwarf, as presented in the AD&D Birthright rulebook, has a few notable differences from the standard 5th edition dwarf template. Most unbalancing, however, is its resistance to bludgeoning damage. This is kind of a big deal, and can't really be compared to the dwarf's natural poison resistance (which it would also have). Resistance (defined both in the Cerilian dwarf's context and the use of the term in 5th edition) cuts damage from said source in half.
It was said to me by a friend whose game design instincts I trust that Cerilian demihumans were created to be rare and kind of scary, and that doesn't really play into 5th edition's "play anything!" mentality. Giving the Cerilian dwarf double resistances feels greatly unbalanced, but I also want to avoid completely throwing away the Cerilian dwarf's flavor. Nevertheless, they are essentially the Player's Handbook mountain dwarf in most other respects.
The Birthright rulebook calls Cerilian dwarves out as being incredibly heavy and dense creatures, upwards of 300 (!) pounds standing between 4 and 4 1/2 feet. That's crazy dense, but they are meant to be "true children of the mountains" and it's an interesting quirk that I think we can work with when determining what to do with the bludgeoning resistance.
Here's my pitch for the Cerilian dwarf that keeps its advantage against bludgeoning weapons:
Ability Score Increase: Your Strength score increases by 1 and your Constitution score increases by 2.
Speed: Your base speed is 25 feet. Your speed is not reduced by wearing heavy armor.
Size: Your size is Medium.
Darkvision: Out to 60 feet, as standard dwarves.
Dwarven Resilience: Resistance to poison and advantage on saving throws against poison, as standard dwarf. In addition, you suffer two fewer points from any source that inflicts bludgeoning damage. If you possess another feature or feat that also reduces damage (such as Heavy Armor Master), this reduction stacks.
Dwarven Combat Training: As standard dwarves.
Tool Proficiency: As standard dwarves.
Stonecunning: As standard dwarves.
Languages: Cerilian dwarves speak Karamhul and one other language of their choice.
So we have a few changes, but the Cerilian dwarf is looking a lot like the mountain dwarf in a lot of respects. However, they trade the free armor proficiency and a point of Strength increase for two points of damage reduction against bludgeoning attacks (damage reduction is still a precedent in 5th edition).
I'd have to see how this plays out in progress, but it keeps some of the flavor without being ridiculously powerful against certain foes. "Situationally overpowered" is never a good thing, but a Cerilian dwarf with Heavy Armor Master is still reducing 5 points of damage from any bludgeoning source; nothing to scoff at.
The other option is, of course, to just say that Cerilian dwarves are mountain dwarves. They fit just fine and the loss of the damage reduction probably wouldn't be completely awful.
The Cerilian elf feels like the easiest of the races to bring forward. They are, with almost no contest, exactly like the Wood Elf in the Player's Handbook. The only thing that makes them sort of weird is that subrace's bonus Wisdom point. To explain, Cerilian elves quite pointedly lost their conflicts with humans because of the latter's possession and use of divine magic, which was outside the elves' ken. They are mighty magic users, and can be true wizards without possession of a bloodline.
To that end, I feel it is reasonable to have the Cerilian elf (Sidhelien) gain a +1 bonus to Intelligence rather than Wisdom, but I see no other changes particularly necessary. I'm happy to entertain suggestions to the contrary!
This one's a bit trickier. Cerilian halflings are very unique; they aren't even from the "normal" world originally, and their powers reflect this unusual heritage. In the Birthright rulebook, Cerilian halflings possessed a sort of "shadow sense" that allowed them to detect evil, undead, or necromantic magic. This is quite similar to the 5th edition paladin class's Divine Sense ability (the PDF I keep linking to had the same idea, and I think it's a good one!).
More troublesome is the ability to use powerful transportation magic when near places and times that the Shadow World (the now-scary place from whence the halflings originally hail) is close to the real world. Dimension door and shadow walk were quite powerful abilities, and even though they were heavily restricted to but thrice a week, that's still a bit more mobility than many Dungeon Masters would like for a first level character. It was also kind of a pain to adjudicate; you had to be able to tell the player what the weather was like, what time it was, what kind of "creepy factor" the surroundings had, is it raining, et cetera in order to determine their percentage success chance.
Great for your improv skills, not so great for just getting on with it.
I think it's still possible to keep, but we have the precedent of the drow elf subrace for delayed ability acquisition.
Further, the Cerilian halfling isn't very much like other halflings. They're not described as particularly lucky or flighty, and are probably some of the most tragic and sorrowful races around. So I think we can strip out Lucky from the base halfling (I know, sacrilege! But not all halflings are kender, and that's its own rant) to help balance the scales a bit.
Ability Score Increase: Your Dexterity score increases by 2 and your Wisdom score increases by 1.
Speed: Your speed is 25 feet.
Size: Your size is Small.
Brave: As standard halfling.
Halfling Nimbleness: As standard halfling. Man, this ability is highly underrated.
From Shadow: This ability grows more powerful as the halfling reaches higher levels of experience.
- At first level, as an action, you may open your awareness to know the location of any fey, fiend, or undead with 60 feet of you that is not behind total cover. You know the type of being whose presence you sense, but not its unique identity. Within the same radius, you can detect the presence of magic from the necromantic school. You must complete a short or long rest before you can use this ability again.
- Upon reaching 3rd level, the halfling may use the misty step spell while standing in any condition of dim or darker lighting (such as a crowded tavern, a wilderness cave, or conditions or moon or starlight). You must complete a short or long rest before you can use this ability again.
- Upon reaching 7th level, the halfling may also use the dimension door spell under the same conditions. You must complete a long rest before you can use this ability again.
I think this is a good compromise and doesn't completely throw away what the Cerilian halfling was once capable of doing. It also stops first level people from using fourth level spells.
If you wanted to scrap this entirely, I'd recommend simply using the Player's Handbook stout halfling. No harm there.
So that brings this first pass to a close. I welcome comments and feedback, of course. Can't very well work in a vacuum, can I? Unless I designed games in space. Hmm...
Who wants to fund a Kickstarter to send me to space so I can design games up there?