One of my favourite series of DRAGON magazine articles was the “Vs. …” series in 2001, which dealt with amongst other things “…Duergar, “…Elves”, “…Goblins” and even “…Psionics”.
They were short 1-2 page articles designed to help players overcome some of the iconic monsters using strategy and common sense.
This is my attempt at a similar article for PFRPG Derro.
Expect the Unexpected
Unlike their duergar cousins, derro don’t have natural invisibility spell-like abilities but do have a racial bonus to Stealth, the ability to lower the illumination level using their darkness spell-like ability and can distract foes using ghost sound. All this makes them great at setting ambushes, so expect the unexpected and unless you possess at low-light vision and/or darkvision, be sure to have spells or magic items that can provide magical illumination to offset the various penalties (non-magical torches and sunrods are ineffective against magically induced darkness).
The Trouble with Spell Resistance
All derro have SR14, which means that low level spell-casters will have a difficult time making the caster level check to directly affect them with their magic. Area effect damage dealing spells such as fireball are also affected, so using spells that alter the environment to counter derro or buffing your own abilities may be preferable. At about 5th level, spell-casters have ~50% chance of affecting derro with their magic but even at 10th level, there is a 20% chance the derro will successfully resist.
Spell resistance works both ways however. Depending on your GM’s ruling, SR can inhibit a derro’s ability to sue magic items that duplicate spells or spell-like effects such as scrolls, wands and other items. For common derro this can be an issue, but most savants are at least 5th level and should be able to use these items successfully 50% of the time.
Although it certainly adds an extra roll to any combat resolution, taking advantage of the potential chaos and unpredictability of spell resistance on both sides of the equation can lead to some interesting scenarios.
Buff that Fortitude Save
Derro use poisoned weapons a lot, particularly incapacitating or amnesia causing poisons, in order to take their opponents captive, so a good Fortitude save is essential. Likewise their innate spell-like abilities that can weaken and disorient an opponent, dazzle and sound burst, are resisted with Fortitude saves so having a high Con or the Great Fortitude (and Improved Great Fortitude) feat is helpful.
Try and Keep Your Distance
Many derro weapons such as the signature aklys and fauchard (or the various suggested alternatives in a previous post) are primarily used to variously trip, disarm, entangle and/or then grapple in order to then pin and tie opponents aiming to capture rather than kill.
Although the fauchard has reach and the aklys a 20′ range, staying beyond this effective range if possible negates much of a derro mob’s ability to collectively subdue their targets, although it does open you up to their repeating light crossbow fire with poisoned bolts and their savant’s spells.
Don’t Fall Over or Get Up Quickly
Being forced prone by a trip attack is generally a bad thing in combat with derro, so having a good CMD helps and being a Monk with a high Wis bonus or 3rd+ level with Maneuver Training helps. Although there is a benefit to being prone for avoiding ranged attacks (+4 bonus to armour class), the inability to fire a ranged weapon and penalty to both making (-4 penalty to melee attack rolls) and avoiding melee attacks (penalty -4 armour class) includes grappling attacks and is a major concern… so don’t fall over if you can help it.
If you’re forced prone get up off the ground as quickly as possible as you’ll most likely be grappled in the next round. This uses a standard action unless you have Monk feat Ki Stand or the Rogue Talent Stand Up and provokes an act of opportunity unless you have Ki stand, so it’s really best try not to fall over and let the little guys grab you in the first place…
Although not relevant if you’re using a crossbow or firearm, feats such as Prone Shooter or Prone Slinger don’t really offset the detrimental effects of being prone in a melee situation with a mob of derro intent on subduing you unless you also have the Point Blank Shot and Precise Shot feats. That’s 3 feats you’ll need… better to just not fall over.
Did I mention you should just not fall over?
Strike at the Head of the Snake
Most derro bands aim to capture rather than kill their opponents and although insane, they are usually too cowardly to fight to the death, particularly if their savants are killed, so bear that in mind and try and neutralise their leaders first and force a rout.
Derro savants themselves are usually 3rd-8th level sorcerers, although alchemists, cave druids, (unchained) summoners and even clerics are suitable alternatives. If your GM has access to Occult Adventures, savants with occult classes such as mesmerist, occultist, and psychic are also possible options and the cytillesh warped derro magister from the Occult Bestiary makes an interesting variant leader.
Fighting against derro savants is an article in itself…
Related Post: Vs. Savants (TBA)