How would one create a balanced dragon PC?

Question

I'm running a DnD 5e campaign and had a dragon-born sorcerer with Draconic Bloodline as a sorcerous origin that used the level 9 Wish spell to wish to become a "true dragon."

Are there any rules about having dragons as PCs? If so, where? If not, how would you go about making it somewhat balanced?

Background

An excerpt from the wish spell:

You might be able to achieve something beyond the scope of the above examples. State your wish to the DM as precisely as possible. The DM has great latitude in ruling what occurs in such an instance; the greater the wish, the greater the likelihood that something goes wrong. This spell might simply fail, the effect you desire might only be partly achieved, or you might suffer some unforeseen consequence as a result of how you worded the wish.

I was considering going with the "the spell failed" option, but decided to have a little fun with it. I warned him about the chance of it going horribly wrong, but he said it would be out of character for his PC to turn down any opportunity no matter the risk.

So I set up a roll table: 00-10 killed him or similar, 11-35 turned him into an egg or against the party or a few other creative things, 36-50 the spell just failed with all of the negative effects of the wish spell gone wrong, 51-80 gave some cosmetic changes, 81-97 adjusted stats a little (can no longer hold weapons an shields but breath weapon is stronger etc.), 98-99 and it actually worked.

Of course he rolled a 99. I gave him exhaustion and said he needed time to recover from the ordeal, but I really need time to figure out what to do with him.

Answer 1

I would treat this as if the sorcerer had cast True Polymorph (another 9th level spell) and concentrated for the entire duration to make the transformation permanent. Since you subjected the sorcerer to great additional risk to use Wish to become a dragon (and the sorcerer really wished to be a dragon) you should treat this as a change in reality rather than a magical effect that can be dispelled.

True Polymorph allows a creature to be turned into any other creature with the same or less challenge rating. Any of the adult dragons in the monster manual should be appropriate permanent forms for the sorcerer. For flavor he should probably turn into the same type of dragon as the dragon in his draconic heritage for his bloodline.

Since permanently being an adult dragon via True Polymorph isn't expected to break the game, being an adult dragon (which can't be dispelled) shouldn't break the game either.

Wishing at lower levels

A lower level character might discover a ring-of-game-breaking-wishing (or its equivalent) and make this wish. Since True Polymorph isn't a spell of 8th level or lower, characters shouldn't expect that their wish be successful. If the character isn't careful in how they word their wish they could become a stone dragon (a statue), temporarily a dragon, a specific dragon who lives somewhere else or on another plane, a dragon that slowly loses its memories and pre-dragon personality, etc. If they are careful in how they word their wish they can still receive only a partially achieved effect and become a wyrmling (or young dragon if the party is in the 7th-8th level spell levels).

Answer 2

Wishes: "Be careful of what you wish for, since you are sure to get it." (old adage)

Are there any rules about having dragons as PCs?*

You are in the area of rulings more than rules.

If so, where?

Some places to get ideas for your ruling would be in CH 4, DMG, creating NPC's and the optional villain classes. This is to compare the powers of a dragon with the powers of a given level of NPC. Also take a look at the DMG page 285-289 on variant class options. Then look at how CR is arrived at in the DMG for a given monster that you custom make. That may not give you a balanced new PC type, but it can help you get in the ballpark.

Consider the challenge rating of the dragon. A party of 4 should be able to handle a CR equal to their level. If your players are level 10, adding a young gold dragon is similar to adding 2, 3, or 4 tenth level players to their party. (Depends on how well your players handle monsters in that CR). Adding an adult gold dragon is like adding 2, 3, or 4 level 17 characters to the party, again, depending on how good they are at harder or deadly challenges. See page 9 discussion on Challenge in the Monster Manual.

For example, a party of 4 3rd level characters should find a monster with challenge rating of 3 to be a worthy level of challenge, but not a deadly one.

If not, how would you go about making it somewhat balanced?

Without a lot of play testing, hard to say. With that caveat in mind ...

You set him a high bar, and he cleared it with a dice roll; D&D does that sometimes. Some points to go with the excellent reply by Cirdec.

How old is he in dragon form?

Proportional or direct age?

• From the table on page 86, if you choose a 1:1 ratio, he is a young gold dragon (age 20, 30, 40, etc). CR = 10. The powers for that are in the Monster Manual on page 115. That's a fairly powerful creature, with flying, and water breathing, etc. A high level sorcerer is no slouch himself.
• If you choose the proportional level of maturity to make him an adult gold dragon, he has legendary actions and can change shape into a beast with CR less than 17 (CR of that age gold dragon). Compare that to a NPC human Mage CR 6 at 11th level, access to fifth level spells. (MM, p. 347). Archmage NPC, access to 9th level spells, CR 12. (MM, page. 342). That is likely not balanced with his fellow adventurers and their abilities.

1. How old is the sorcerer?
   Early 20's? 30's? 40's? 50's? Suggest that he is that age, and thus a young golden dragon. (Depending on the character level of the sorcerer and the party, this may suffice. Or not).

2. How old of a dragon are you willing to make him?
   Humans live less than a century (so 80-100 would be a long life) years (PHB. p. 31) Dragons can live 800+ (DMG p 86). That's roughly 10 to 1 in proportion.

3. What level is he; what level are the other party members?
   If they are at level 13, it's one thing, if they are at 19 or 20 they are in the epic tier. Consider their CR rating using the tools in DMG, p 273 - 279 to compare theirs to his in his new form.

4. Balance?
   If you allow proportional age (adult gold dragon) and the party wish to keep playing, you may need to scale his abilities into somewhere young and adult. His change shape power may need a limitation, or removal. (Depending on level, allowing him to use that to turn into his old sorcerer self is likely a power downgrade). He isn't a sorcerer anymore, he's a gold dragon ... who can change shape into humanoid or beast form. (At no higher CR than the gold dragon is, p. 114, MM, which is CR 17. That's powerful).

5. In between?
   With a bit more work, you might be able to find something in between adult and young, or between wyrmling and young if you take Cirdec's conservative approach. Tweak it by applying various DC's (with a chance of failure) on his Young or Adult powers to keep him within bounds of your other players. Trying to tie this to "PC levels" in the "Gold Dragon Class" is something that would need play testing to get into the ballpark. Allowing him to progress in level to Adult gold looks hard for balance unless you vary skills and attributes. The other players, human, might be dead by then, although elves, dwarves, and half elves may live long enough to see their friend grow into an awesome beast.

Recommendation

If you proceed with this, he's a young dragon with as many dragon years as human years.

The adventures that this change can bring to the party, in terms of how NPC's, lords, wizards, thieves, sellswords, kindoms, etc react to a gold dragon running about could be great fun. He could end up as a wanted man/dragon, his likeness up in all of the post offices on the King's road ...

Suggest also: Disadvantage on persuasion checks for anyone owning livestock. :)

Afterthought: if what you were looking for is a way to have levels of progression for the PC along with the rest of the party, a way to moderate the aspect of power that is HP is to set the hit dice (young) at the sweet spot of young (about 50-70 years old) and then reduce some proportionally for the age the sorcerer is when he turns into one. (If he's 25, Reduce by a fraction so that there is room to grow).

This is if the "PC dragon" is to be able to grow and achieve more ability as the other players in the party progress. Do the same with reducing the number of HD for breath weapons. Or make the recharge harder to score on a die.

If you don't want to do that, then the points Cerdic made about making a wyrmling or a young dragon still give you room to vary the hit dice if you think one is too weak or the other too strong, compared to the rest of your party.

Answer 3

If this wish means they will become an adult gold dragon because his dragonborn sorcerer has the gold dragon bloodline, that means changing from a medium-sized creature to a huge creature. In that case, then here are some things I think would be useful:

• No more implements since dragons don't really have the ability to hold such a small item.
• Lose all other languages with the exception of Draconic and Common.
• Lose all use of any unnatural armor.
• The increase in AC from dragon scaling would no longer be added because you have the scaling from being a dragon.
• He might gain wings, but have no flight speed. Perhaps clumsy flying.
• As for the sorcerer levels, as far as spells go, I think you should be required to retrain all your spells to only damage spells and as close to fire as possible. This means no ray of frost, for example.
• I think it would be fair to never allow the character to use the wish spell again.

In summary: Lose armor, no implements, no weapons other than the bite, claw, and tail that you would gain; tetrain spells to better suit your new role; and to forever be restricted from ever using wish.

And since he is now beyond the other characters, he should no longer be allowed to gain experience as a PC. He should gain experience as a dragon. Learning to use his new form to its full potential should not be allowed. He should never gain perfect flight. He should never be able to use his breath weapon like a dragon (i.e., rolling to reuse). If at any point he tries to manipulate the situation to gain perfect flight or breath weapon recharge, he should have to make a will save to attempt to keep his sense of self. On a failed save, he loses his character abilities and character. The dragon becomes, for all intents and purposes, an enemy and he loses his character.

This is my thought on a PC using wish to become a "true dragon".