The Charm of Swarms
You know what I like? Swarms of things. Well, okay, no, not really. I wouldn’t like to come home at the end of a long day at work and find a swarm of, well, just about anything waiting for me when I got there. But, in games (or other fantasy media, for that matter), where I don’t have to actually deal with the swarm myself, I think swarms are cool. Not too terribly long ago we previewed a spell from Advanced Arcana III whose sole purpose was to let you transform into a swarm of crows, because that’s a cool thing that people sometimes do in fantasy settings, and, until recently, it wasn’t really something you could do in Pathfinder.
A similar milestone in the history of the game which I am particularly fond of was the day that they threw out the restriction that a druid’s animal companion had to be an animal, and started including vermin. It had never made sense to me that giant spiders, centipedes, and bees, creatures that would be considered “animal” by any real-world definition, couldn’t be made into animal companions because in game terms, they were vermin, instead. In fact, I was amazed to discover just how many crazy things you could have these days for your animal companion, and more than a few of them are vermin.
That got me thinking—why not swarms? It’s a common enough thing to see in fantasy media, the guy with the intense bond with an entire swarm, which acts as an extension of his will. So, I rolled up my sleeves and decided to bring swarms to all the druids and rangers out there who’ve been waiting for their own sentient beehive companion (and a couple others, to boot). Enjoy.
Swarm Companions
Swarm companions follow the same rules as normal animal companions, advancing their Hit Dice and other abilities as normal for animal companions. Swarm companions can be trained as if they were normal animals using the Handle Animal skill. If the swarm is comprised of vermin, it also uses the vermin companion rules outlined in Ultimate Magic.
Traits: Swarm companions possess all of the normal traits of a creature of the swarm subtype, except as noted here. Regardless of the size of the component creatures, a swarm animal companion takes half damage from slashing and piercing weapons (meaning that even if the swarm is made up of Diminutive or Fine creatures, it will still take half damage from slashing and piercing weapons). Additionally, swarm animal companions do not automatically possess the distraction ability, or interfere with spellcasting, concentrating on spells, or the use of skills that require concentration or patience (although some swarm animal companions may possess or gain this ability, as indicated in their individual entries). Finally, a swarm animal companion does not deal swarm damage to its master (unless somehow charmed or compelled to do so). Further, a swarm animal companion can be taught not to harm other specific individuals. Doing so counts as one trick for the purposes of the number of tricks the swarm possesses, but allows the swarm to be taught any number of individuals not to harm.
Dispersing: A swarm animal companion that is reduced to 0 hit points disperses as described under swarm traits. After 1d4 days, the swarm has sufficiently recollected itself and replenished its numbers, as the various component creatures (and other, similar creatures that were never part of the swarm before) instinctively converge on the swarm’s master.
Mindless: Swarm companions made up of animas that have no Intelligence score possess the mindless trait. In spite of this, such companions may learn one trick, plus additional bonus tricks as normal for an animal companion. If a mindless swarm animal companion gains an ability score increase (at 4 Hit Dice, 8 Hit Dice, and so on), the druid can apply this increase to the companion's Intelligence, changing it from — to 1, at which point the companion loses the mindless quality and is able to know up to 3 tricks per point of Intelligence, plus the additional bonus tricks, as per Handle Animal. Mindless swarm animal companions have no skill points or feats as long as they have the mindless quality.
Centipede Swarm
Starting Statistics
Size Diminutive; Speed 30 ft., climb 30 ft.; AC +4 size; Attack swarm (1d4 plus poison); Defensive Abilities swarm traits; Ability Scores Str 1, Dex 19, Con 8, Int -, Wis 10, Cha 2; Special Qualities darkvision 60 ft., tremorsense 30 ft.
7th-Level Advancement
Ability Scores Str +1, Dex +2, Con +2; Special Attacks distraction (DC 10 + 1/2 the centipede swarm’s Hit Dice + the centipede swarm’s Constitution modifier)
Poison (Ex): Swarm—injury; save Fortitude DC 12 + 1/2 the centipede swarm’s Hit Dice + the centipede swarm’s Constitution modifier; frequency 1/round for 6 rounds; effect 1d4 Dex damage; cure 1 save.
Rat Swarm
Starting Statistics
Size Tiny; Speed 15 ft., climb 15 ft., swim 15 ft.; AC +2 size; Attack swarm (1d6 plus disease); Defensive Abilities swarm traits; Ability Scores Str 2, Dex 15, Con 13, Int 2, Wis 13, Cha 2; Special Qualities low-light vision, scent
7th-Level Advancement
Attack swarm (2d6 plus disease); Ability Scores Con +4
Disease (Ex): Filth fever: Swarm—injury; save Fort DC 10 + 1/2 rat swarm’s Hit Dice + the rat swarm’s Constitution modifier; onset 1d3 days; frequency 1/day; effect 1d3 Dex damage and 1d3 Con damage; cure 2 consecutive saves.
Vampire Bat Swarm
Starting Statistics
Size Diminutive; Speed 5 ft., fly 40 ft. (good); AC +4 size; Attack swarm (1d6); Defensive Abilities swarm traits; Ability Scores Str 3, Dex 15, Con 11, Int 2, Wis 14, Cha 4; Special Qualities blindsense 20 ft., low-light vision
7th-Level Advancement
Attack swarm (2d6 plus blood drain); Ability Scores Dex +2, Con +2
Blood Drain (Ex): Whenever a vampire bat swarm deals swarm damage to a living creature, it regains a number of hit points equal to 1/2 the damage dealt.
Wasp Swarm
Starting Statistics
Size Diminutive; Speed 5 ft., fly 40 ft. (good); AC +4 size; Attack swarm (1d6 plus poison); Defensive Abilities swarm traits; Ability Scores Str 1, Dex 13, Con 10, Int -, Wis 12, Cha 9; Special Qualities darkvision 60 ft.
7th-Level Advancement
Attack swarm (2d6 plus poison); Ability Scores Dex +4
Poison (Ex): Swarm—injury; save Fort DC 10 + 1/2 the wasp swarm’s Hit Dice + the wasp swarm’s Constitution modifier; frequency 1/round for 4 rounds; effect 1 Dexterity damage; cure 1 save. The save DC is Constitution-based.