Adding that 20th Sorc level to a Great Wyrm Solar Dragon

[Arkat]

How would you add that last Sorc level to a Great Wyrm Solar dragon?

According to Bestiary 4, a Great Wyrm Solar dragon casts as a 19th level Sorc. A Great Wyrm Solar dragon also has 29d12 HD (188.5 HP not counting CON, Toughness, etc.) and is a CR 21. The base saves for a Great Wyrm Solar dragon are Fort 16, Reflex 16, Will 16.

I'd like to add that last level of Sorc to effectively make the dragon a 20th level Sorc.

How would you do it?

Add a d6 HD or a D12 HD?

Would you add that extra +1 to Will saves as a 20th level Sorc gets that extra +1, or would you just leave its saves alone?

Obviously, you would add the extra 9th level spell and the extra castings per day, so no problem there.

I'm guessing the CR would also go up by one because that extra Sorc level would add +1 to the CR because Dragons are generally assumed to take the Caster role.

How about the BAB? A Sorc going from 19th level to 20th level gets a +1 to its BAB. Wouldn't the dragon also get a +1 to its BAB (for a +30 BAB total) if it gets that 20th Sorc level?

I'm not going to adjust its ability scores by +4, +4, +2, +2, 0, and -2 even though RAW, I could. Seems a bit OP for adding just 1 Sorc level.

Thanks.

[Azothath]

seems more like GM Advice. Exactly which spells is a matter of taste and experience along with thematic choices but RAW has a list under Ancient.
It gains casting ability, not class levels, class feats, and class HD... Mythic goes a bit bonkers and Wyrms are mythic.

Solar Dragon age categories
 Spells: A dragon knows and casts arcane spells as a sorcerer of the level indicated in its specific description. Its caster level depends on its age, as shown for each type.
 Spell-Like Abilities: A dragon's caster level for its spell-like abilities is equal to its total Hit Dice.
Solar Dragon, Ancient

Red Dragon, (Mythic) Wyrm

[Mysterious Stranger]

If it helps the way Hero Designer, does it is to add what a 1st level sorcerer gets. So, no increase on BAB, FORT or REF saves, but a +2 on Will saves and d6 extra for HP.

[happykj]

There is a drider NPC with cleric levels in Rival Guide.

Basically she get all the class abilties as normal and stack the caster level with her drider's spellcasting ability.

I would prefer to make it simple by adding the caster level only instead of adding everything.

[glass]

LTTP, there doesn't seem to be a straight-forward concrete answer so far:

A great wyrm solar dragon normally casts as a 19th-level sorcerer, but has no actual sorcerer levels. If they take one actual sorcerer level, they will cast as a 20th-level sorcerer but will have the other features of a 1st-level sorcerer (including +2 Will, an extra HD, and the associated hit points and skill ranks).

[Arkat]

glass wrote:

LTTP, there doesn't seem to be a straight-forward concrete answer so far:

A great wyrm solar dragon normally casts as a 19th-level sorcerer, but has no actual sorcerer levels.

True enough.

glass wrote:

If they take one actual sorcerer level, they will cast as a 20th-level sorcerer but will have the other features of a 1st-level sorcerer (including +2 Will, an extra HD, and the associated hit points and skill ranks).

This makes sense to me.

Thanks!

[Arkat]

glass wrote:

LTTP, there doesn't seem to be a straight-forward concrete answer so far:

A great wyrm solar dragon normally casts as a 19th-level sorcerer, but has no actual sorcerer levels. If they take one actual sorcerer level, they will cast as a 20th-level sorcerer but will have the other features of a 1st-level sorcerer (including +2 Will, an extra HD, and the associated hit points and skill ranks).

Been doing some further thinking about this.

Taking that 1st level of Sorc would make him a 20th level (Sorc) caster, yes?

How many EXP would that 1st level cost?

Zero?
2,000?
1,050,000?
Something else?

[Dasrak]

Arkat wrote:

How many EXP would that 1st level cost?

Experience points are only relevant for player characters. In which case, use the monsters as PC's guidelines:

http://legacy.aonprd.com/bestiary/monstersAsPcs.html

So a Great Wyrm Solar Dragon is CR 21, so the amount of experience points required to gain one level of Sorcerer is the same amount that would be required for a hypothetic level 21 character to reach level 22. This is outside of the scope of the actual rules for leveling up, but it should be significantly higher than the amount of experience required to go from 19->20.

As a rough estimate, this should be about 2,000,000 experience.

[Diego Rossi]

CRB - Beyond 20th Level wrote:

Experience Points: To gain a level beyond 20th, a character must double the experience points needed to achieve the previous level. Thus, assuming the medium XP progression, a 20th-level character needs 2,100,000 XP to become 21st level, since he needed 1,050,000 XP to reach 20th level from 19th. He’d then need 4,200,000 XP to reach 22nd level, 8,400,000 XP to reach 23rd, and so on.

4,200,00 xp.

Two CR 25 and a CR 21 opponents if you are alone.
Or 21 CR 20 opponents.

The second option could be done with minimal risk if you can find the targets.
An LN creature can even have the motivation to do it without caring too much about the consequences, as long as they are for a "higher" goal.