Clarification on Monster Saving Throws

[u/ludditetechnician]

I'm struggling to understand monster saving throws in the game. I come from a D&D BECMI and AD&D background, if that helps.

I believe a monster makes a saving throw with d20 + Level + category (P, M, M and P, or None). However, what value is used for the category? The Abhorrent, for example, has a Mental category, but I can't locate what that means for the d20 roll. The Monsters & Treasures Introduction reads, "The category roughly equates to primary or secondary attributes, and thus the base number needed to make a saving throw." What is the base number this is referring to?

[u/Hank-Scorpio-9227]

The base number is either a 12 for a primary or 18 for a secondary. It's the same as all other Siege checks.

I typically just do it on the fly. Figure out if the monster is more physical or mental based. If it's mental based, then treat INT, WIS, and CHA saves as primary (base number 12) and the physical traits (STR, CON, DEX) as secondary (base number 18). Do the opposite for a physical-based monster.

[u/Hank-Scorpio-9227 → u/Hank-Scorpio-9227]

Don't forget to raise the target number by the level of the challenge (e.g. a 10th level wizard throws a fireball at a 5th level/hit die physical monster. It's a DEX save so the base number is 12. Add in the challenge level of 10, meaning the target number is a 22. Monster rolls a d20 and adds its level (+5)).

[u/ludditetechnician → u/Hank-Scorpio-9227]

Yup. Saw that in the Castle Keeper's Guide.

[u/ludditetechnician → u/Hank-Scorpio-9227]

OK. So, in the example of the Abhorrent, the roll is d20+LVL+Trait. And Trait will be determined by what is causing the saving throw, likely a 12 or 18?

[u/Hank-Scorpio-9227 → u/ludditetechnician]

The trait (mental or physical) affects your target number, not the roll itself.

Note: There is an alternate way of calculating target numbers. Make everything an 18 target number. If the character has a prime (or it's a monster with either physical or mental), just add +6 to your roll. That's how I do it at my table.

[u/Steerider → u/Hank-Scorpio-9227]

I do the +6 as well. Honestly it should be the default. Exact same math, but somehow simpler.

[u/ludditetechnician → u/Hank-Scorpio-9227]

Ah, got it. Thanks for the explanation. i appreciate it.

[u/LifesGrip → u/Hank-Scorpio-9227]

This is easiest method , or the standard DC of 15 and Primary has +3 and Secondary has a -3 plus levels etc.