CR modifier of a template?

[SnowyJune9703]

Suppose that there's a template, whose only content is to give the base creature ability to cast spells like a x-th level druid/cleric/wizard/sorcerer/... . How much should the template's CR modifier be?

Few monsters have similar abilities, so it's been a real problem for me to find out the exact CR modifier. (Obviously the CR offset shouldn't be more than x)

a comparison is the [Spellcasting Class] Creature templates. these templates grants 5 spell slots, aside from a few important class abilities of the related class. These templates have a max CR modifier of +3.

[deuxhero]

Does the creature speak and have hands? If you just want a few spells just give them ranks in UMD and give them a scroll of what you want to cast. No template needed.

[Dasrak]

Snowyjune9703 wrote:

Suppose that there's a template, whose only content is to give the base creature ability to cast spells like a x-th level druid/cleric/wizard/sorcerer/... . How much should the template's CR modifier be?

This is not a good use of the template rules, and there is no way you could get a "one-size-fits-all" CR adjustment on a template like that. If you put the spellcasting powers of a 7th level wizard on a CR 1 monster then that creature is going to get phenomenally more powerful; probably CR 5 or CR 6. If you slap the spellcasting power of a 7th level wizard on a CR 20 monster it's going to have a negligible impact on the creature's combat potential and will mostly be a utility option... so CR 21 is being generous.

This sort of situation is much better handled by adding PC class levels to the monster in question. This gives it HD progression to better match its new CR, and the rules for CR when advancing with PC class levels are a pretty good ballpark. Alternatively there's the class graft system from Pathfinder Unchained, although personally I prefer just adding class levels.

[SnowyJune9703]

Dasrak wrote:

Snowyjune9703 wrote:

Suppose that there's a template, whose only content is to give the base creature ability to cast spells like a x-th level druid/cleric/wizard/sorcerer/... . How much should the template's CR modifier be?

This is not a good use of the template rules, and there is no way you could get a "one-size-fits-all" CR adjustment on a template like that. If you put the spellcasting powers of a 7th level wizard on a CR 1 monster then that creature is going to get phenomenally more powerful; probably CR 5 or CR 6. If you slap the spellcasting power of a 7th level wizard on a CR 20 monster it's going to have a negligible impact on the creature's combat potential and will mostly be a utility option... so CR 21 is being generous.

This sort of situation is much better handled by adding PC class levels to the monster in question. This gives it HD progression to better match its new CR, and the rules for CR when advancing with PC class levels are a pretty good ballpark. Alternatively there's the class graft system from Pathfinder Unchained, although personally I prefer just adding class levels.

That's right, the CR modifier depends on the base creature's CR. So, say I'm going to make a Wizard 19 Elf 20-buy NPC(CR19) to have the ability to cast cleric spells like a 13th cleric, then what's the CR modifier? Is that +1, +2 or so? ( In such situation, adding PC class levels is not possible)

P.S., actually the [Class] Creature Template's CR modifier is also a progression, rather than a fixed number. However that's a slightly different situation.

[SnowyJune9703]

SnowyJune9703 wrote:

Suppose that there's a template, whose only content is to give the base creature ability to cast spells like a x-th level druid/cleric/wizard/sorcerer/... . How much should the template's CR modifier be?

Few monsters have similar abilities, so it's been a real problem for me to find out the exact CR modifier. (Obviously the CR offset shouldn't be more than x)

a comparison is the [Spellcasting Class] Creature templates. these templates grants 5 spell slots, aside from a few important class abilities of the related class. These templates have a max CR modifier of +3.

Well looks like the CR modifier is not a fixed number. Then I'll have to add some restrictions:

What's the approximate value of the modifier when 1/2 base CR <= x <= base CR, and the base creature has a SCL of more than x?(e.g. Base creature = Elf Wizard 19, x = 15)
And what's the approximate value of the modifier when x < 1/2 base CR, and the base creature has a SCL of more than x?(e.g. Base creature = Elf Wizard 19, x = 6)
And what's the approximate value of the modifier when x < 1/2 base CR, and the base creature can't cast spells?

I think that should make the question clearer.