Another Dragonsfoot Contest entry....
In a disused portion of the sewer, sits a shrine made of hundreds of rat skulls, bound together with shreds of rat skin. The skulls range from the teeny, soft skulls of pinkies, to the massive skull of an ogre who fell victim to arourthropy. While the vault around it is caked in inches of rat feces, the shrine itself is clean, the bone gleaming white, save where it is stained rust from tracks of blood across it.
Falvic, the King of Rats, dwells nearby.
A minor demon-deity, Falvic's purview is rats of all sorts... tiny rats. Giant rats. Wererats. Politicians. His influence stretches through the halls of power, and he grows in strength wherever rats may thrive. To that end, he fosters lycanthropy and other diseases, knowing an excess of waste will allow his rats to flourish. When he gains power, he diverts funds away from city maintenance, so that rats will have more places to thrive. He has no real agenda, save an increase in the number of rats; left unchecked, he will overrun a world in rats, only to have those rats turn on each other and devour themselves.
Sometimes summoned by wererats, Falvic more often appears when rats grow out of control in an area. His first action, before he is able to manifest, is to construct a shrine; this takes 1d6 days, and might be interrupted before it begins if people notice that rats are gathering rat skulls and dragging them off. His manifestation causes all cats within three miles to simultaneously yowl in alarm; cats intelligent enough to communicate (such as wizard's familiars) can tell that something very wrong, very unnatural, has some to pass, but won't know exactly what. His manifestation usually appears as the dominant humanoid in the area, wearing a long cloak, but with rats scurrying across and even into his body (squirming in through an earhole, tiny rats falling out the nostril) at irregular intervals.
NO. APPEARING: I
ARMOR CLASS: 3
HIT DICE: 7+1 (43 HP, plus bonuses for rats)
% IN LAIR: 85%
TREASURE TYPE: O*3, P*2, , Q*5, S, T
NO. OF ATTACKS: 2
SPECIAL ATTACKS: See below
SPECIAL DEFENSES: Hit only by +1 or better weapons1
MAGIC RESISTANCE: 30%
ALIGNMENT: Chaotic Evil
PSlONlC ABILITY: Nil
Attack/Defense Modes: Nil
Special Abilities: Falvic has several special abilities that make facing him difficult. In addition to his modest Hit Dice, Falvic gains 1 HP for every rat within 30 feet of him; he is usually surrounded by 1d6*10 rats at any time, but may "beef up" if he wishes to 1d6*100. Summon Swarm and other spells which MIGHT summon rats WILL summon rats, adding (spell level)*(caster level) HP to Falvic's total. When surrounded by normal rats, all opponents within 30 feet of him take 1d4+3 damage per round from rat bites. All rats (including normal, giant rats, wererats, familiars, even other planar creatures such as imps who are able to turn into rats*) obey Falvic if they are within 200'; intelligent rats will feel the call of him, but can make a saving throw v. spell to avoid being drawn in. Falvic is also capable of calling more rats to him. Each round, regardless of other actions, 1d6 rats will approach within 30'. If he calls rats to the exclusion of other actions, this will result in 5d6 rats per round.
Falvic can touch 2 rats per round and affect them as if with Animal Growth. If pressed into combat, he attacks twice per round with dirty claws. Any claw attacks made by Falvic will inflict lycanthropy (wererat), though the effects of that will not appear until the next new moon. It is highly suggested that one not fight Falvic during the new moon, or the effects will happen instantly. In addition, he has the abilities of a 7th level druid and a 10th level thief, including spells and scrolls.
Special Weaknesses: Falvic has some weaknesses; some obvious, others not. While his ability to summon rats and draw strength from them is impressive, anything that kills the rats will likewise harm Falvic; a 3 point fireball won't hurt him much, but it WILL kill most of the rats in the area, reducing his health by a like amount. Falvic also takes triple damage from cats of all types, and double damage from weapons made from cats or anointed with cat urine.
*Only applies if rat is one of a few defined forms that they can take. A Type III/Glabrezu demon is capable of polymorphing into any shape, so is not subject to Falvic's control. An imp, able to turn into a rat and one other creature, is.
Use in a Campaign: Falvic can be exceptionally nasty to fight UNLESS you have access to some way of killing large numbers of rats quickly; one or two area of effect attacks and his HP drop to manageable levels, even if he starts the encounter with over 600 HP. If allowed to run unchecked, he will drag a city down into the sewers, filling it with filth and hordes of rats, letting the rats spill into the countryside at need. His status as a minor deity keeps him from entering Sigil, but he would LOVE to find a way to bring cranium rats to the Prime Material.