Summon Nature's Ally- How Does It Work?

[GreyWanderer]

Gang:

This may seem like a stupid question, but did they pick the creatures for the Summon Nature's Ally lists? I mean, if you look at the creatures on a specific list, what is the common factor? The Hit Dice are very different; the Challernge Rating is usually 1-2 points apart - but some are waaay off.

If I were to make a customized list, what is the formula?

Thanks,

Grey.

 

[Hawkson]

also, when it says summon 1,1-3,2-5 are you summoning
1 from the current list
1-3 from the list at the previous level
and 2-5 from 2 previous levels

OR

1 monster with current Hit Die
1-3 monsters with 1 less Hit Die
2-5 monsters with 2 less Hit Die

 

[Prism]

Its based roughly on CR. Lower CR until SNA V and higher after. Unearthed Arcana has some examples

http://www.systemreferencedocuments.org/35/sovelior_sage/unearthedSummon.html

 

[Staffan]

It's mostly based on CR, with the caveat that creatures with useful spell-like abilities shouldn't be available until, at the earliest, one level above their most powerful ability.

For example, a Unicorn can cast cure moderate wounds (Drd 3) and neutralize poison (also Drd 3). Therefore, a unicorn requires a summon nature's ally IV.

 

[Staffan]

also, when it says summon 1,1-3,2-5 are you summoning
1 from the current list
1-3 from the list at the previous level
and 2-5 from 2 previous levels

Yes. Except it's "or", not "and."