Giving Water elementals vulnerability to Fire?

[Toy Killer]

So, I have an encounter Idea in mind where I'm going to take a medium water elemental, give it necromental and then apply the swarm-shifter template (Both templates from Libris Mortis).

I want the encounter to play to the strengths of one of my players whom is playing a red draconic heritage sorcerer with a natural affinity for fire spells, to give him a chance to shine. He has two AoEs on his spell list and I know that at lower levels (6, to be precise), Swarms are difficult to take on without AoE's.

So, the area is a town that was built up on grates, they dammed the river inlet to make fishing more practical. When the world starting going crazy, a massive plague broke out and the royalty of the area hastily decided to break the damn and just flood everyone. So underneath the grates are the decaying and vengeful dead, and when the party arrives, they come out full force as a united vengeance. Problem is, I can explain the area being cold and all, but I can't seem to find a means to give this elemental the 'Cold' Subtype and let the sorcerer really have his hay day. I can always Ad Hoc it (Lord knows I'm doing it a lot for this campaign) but I wanted to see if there is a more 'official' way. One that may give more inspiration...

[Spuddles]

The swarm type takes 50% extra damage from AoEs.

[Doorhandle]

How will he know that it's vulnerable to fire though?

If it was an ICE elemental it would be obvious, but it's generally expected that water beats fire and not the other way round. :smallconfused:

[Toy Killer]

well, the Water elemental is coming from icy water, and I'm describing it as putrid slush with body parts in it. I was going to have icy patches across the battle field to make placement more important (again, played to the Sorcerer. He also has baleful transposition to utilize, and if he uses it on someone in the center of a swarm he's in perfect position to flame hands lay down some hurt).

So, the general gist of the battle is the elemental is able to keep up and alive by switching between being swarm to elemental form and regain some HP, each way. some silent moments in between each switch to build tensions and then the swarm or the elemental comes up through the grates.

[rot42]

The easiest way to give something the [Cold] subtype is with a casting of Mantle of the Icy Soul (Frostburn 101), but that is pretty close to just declaring it by fiat. The same book has the Ice Beast template (139) if your monster can be a construct.

The Ice Paraelemental (Manual of the Planes 180) might fit the bill here.

This encounter sounds like great fun. Be sure to describe drifts of slush in the muck, the water as freezing and cracking as it swirls around the monster, and great gouts of steam sloughing and subliming of it to indicate that fire is particularly effective.

[Toy Killer]

So, I took the Ice Paraelemental advice and this is my final crunch, but I'm not one hundred percent I did it correctly. I waved the size to large, just so I wouldn't need two different markers for the two sides:


The People of ____________
Huge Swarmshifter (Undead parts) Necromental ice paraelemental

Elemental form
Huge undead (Cold, Shapeshifter)
8D12 (48 hp)
Initiave +5
Speed: 30 ft
AC: 19 (-2 size, +5 Dex, +6 natural)
Full attack: Icicle +10/+5
Damage: 2d6+2 and 2d6 Cold
Space/reach: 10 by 10, 15 foot reach
Special Attacks: Chill metal, Create Spawn, Level drain (fort save DC 14)
Special Qualities: Undead, DR 10/+1, cold subtype, Swarm form, Fast Healing 3
Abilities: Str 14, Dex 21, Con -, Int 1, Wis 10, Chr 1
Skills: Listen +12, Spot +12
Feats: Combat reflexes, Dodge, Weapon finesse (Icicle)
CR 7

Swarm Form
Huge Undead (Cold, Shapeshifter)
8d12 (48hp)
Initiave: +5
Speed: 20 feet flying (Poor)
AC: 19
Full attack: - (Swarm attack)
Damage: 3d6 (Cold)
Space Reach: 10 by 10 / 0 reach
Special Attacks: Chill Metal, Create Spawn, Distraction, Swarm, Fear (Will DC 10)
Special Qualities: Undead, DR 10/+1, Cold, Fast Healing 3, Hive Mind, half damage from slashing Piercing
Abilities: Str 14, Dex 21, Con -, Int 1, Wis 10, Chr 1
CR 7


Any constructive critique is still appreciated, and thank you all again for the help! :D