Dryads and Monster Magic

[numenetics]

I'm working on an adventure focused on obtaining the "wood from a dryad's tree" from the Free RPG day adventure, which involves designing a dryad for my campaign. As I'm starting to think through this, it's leading me to a broader question: how should magic and magic-like effects work for monsters? Ogre shamans, etc. seem pretty straightforward: roughly like a wizard or cleric. For something like a dryad, however, it seems like their control over magic should be slightly more predictable (for the dryad, not for the PCs).

For creatures that have inherent affinities with magic or magic-like effects, how should their spells work? Has anyone designed a monster of that type yet? I'm considering limiting the spell check range of the dryad so that there is a narrower degree of variation than if a wizard/cleric were to cast a spell.

Thoughts?

[meinvt]

If you want it to be absolutely predictable just select a spell check number that she always gets when using that ability.

If you want a roll, but a much narrower range of variation, how about multiple dice for the bell curve and bonus? For example, instead of d20+5 for a spell check (giving an average of 15.5 and a range of 6-25 with 30% chance of 11 or lower) you could roll 3d6+5 (giving an average of 15.5 and range of 8-23 with less than 10% chance of 11 or lower).

Alternately, you could just go to a smaller die with a big bonus. For example, instead of the above, use d10+10 for an average roll of 15.5, no chance of going over 20 and only a 10% chance of an 11.

I also suggest you decide whether the ability can be countered via a spell dual. I've been noting in module conversions if a creature ability is "like X" if there is a particular spell that I think could counter it.

[numenetics]

Nice. Those seem like good options, and good advice on thinking ahead about dueling potential.

[moes1980]

I created a dryad for such adventure. I set her up to be able to enslave one creature that she can keep enslaved for as long as she wants. I gave her a bugbear slave that she told to round up a band of goblins to attack the pcs, whose presence and foul desire to damage her tree were sensed once they came into the forrest.

I also gave her a charm spell which was just the "word of command" cleric spell. I gave her a +4 to cast it with a -1 for each casting with the idea being that, thogh a first glance at the beautiful dryad could make a character stay their hand or even protect her by attacking his friends, this charming effect would become less effective as the player gathered his senses and became more aware of was really going on around him.

I also gave the dryad a d4 damage claw attack at +3 with 6 hps and one action die.