Hydromancer?

[Nettlekid]

How would you go about making a character that primarily uses water as a weapon? I'm thinking caster, either Wu Jen or Druid, probably Druid focusing in water spells. (I guess Spirit Shaman also works in that regard. And maybe a Cleric with the right domains.) Now, there are several good water-based spells, but the thing that interests me most is that many of them are Conjuration: Creation. Flashflood and Waterspout in particular are quite cool.

Now, while I'd appreciate potential PrC suggestions and other optimization tips, what I'd like most of all is to find synergistic spells. Any kind of hydromancer in D&D doesn't suffer the usual comic book weakness of a water user-they won't be wanting for water to use, since they can magically summon it. Which means you can rely on having a substantial amount of water in the terrain. And that means that any spells that have some additional effect in water can be reliably used. So, what are some spells with effects like those? I'm expecting that several Electricity spells might react to a watery terrain, and that Ice spells might work to freeze the water and lock it down. What spells work like that?

[Jeff the Green]

Wu Jen probably isn't a standout for this. They don't get many exclusive Water spells and their only elemental class ability is mediocre and comes later than you want to stay in the class. Archivist, Druid, Spirit Shaman, and Wizard are the options I'd consider.

There are a couple of PrCs in Stormwrack. Wavekeeper is mostly underwater-focussed, but Sea Witch might work. I think there's also one or two in Deities and Demigods.

For spells, I've always bee a fan of extract water elemental (Spell Compendium, Druid 6/Wizard 6, and it should probably be added to Wu Jen).

[Phelix-Mu]

How would you go about making a character that primarily uses water as a weapon? I'm thinking caster, either Wu Jen or Druid, probably Druid focusing in water spells. (I guess Spirit Shaman also works in that regard. And maybe a Cleric with the right domains.) Now, there are several good water-based spells, but the thing that interests me most is that many of them are Conjuration: Creation. Flashflood and Waterspout in particular are quite cool.

Now, while I'd appreciate potential PrC suggestions and other optimization tips, what I'd like most of all is to find synergistic spells. Any kind of hydromancer in D&D doesn't suffer the usual comic book weakness of a water user-they won't be wanting for water to use, since they can magically summon it. Which means you can rely on having a substantial amount of water in the terrain. And that means that any spells that have some additional effect in water can be reliably used. So, what are some spells with effects like those? I'm expecting that several Electricity spells might react to a watery terrain, and that Ice spells might work to freeze the water and lock it down. What spells work like that?

As part of a campaign device with some npcs, I created multiple adaptations of the Sandshaper PrC to work with other elemental substances. I put the most work into a Watershaper PrC, adapting the spells granted list, the sandshaping ability, and substituting in a couple class features that couldn't be easily refluffed for water with stuff a Watershaper should be able to do.

*stares at stack of old campaign papers*

If you are particularly interested, I could dredge them up, but it amounts to homebrew, so perhaps this forum isn't the best place to discuss my little side project.

As to your other topic, of how can other spells be used in conjunction with a hydromancer-type concept, the obvious ones that pop into mind are things like control weather and the like, possibly allowing for additional watery-type effects for a hydromancer. For instance, if the hydromancer is around or can conjure sufficient water (flashflood, tsunami, blizzard plus heat, etc), then creating a powerful wind effect (probably hurricane or stronger) should produce a water spout. And water spouts should have additional effects beyond their wind abilities; I'd think maybe some additional bludgeoning damage (perhaps nonlethal) from getting smacked by wind-driven masses of water, and perhaps some type of drowning threat (which always needs to be handled carefully in D&D due to drown mechanics being very lethal).

Otherwise, perhaps things like the handful of temperature-altering spells would be able to cause water to condense/evaporate. Again, the rules hardly cover this, but it probably falls under the auspices of mechanics not made clear by the game follow the kinds of rules found in real life. Thus, ratcheting the temperature in region of moderate-to-high humidity down several temperature bands should cause it to rain (though the limited range of such spells would cause a highly localized rain, especially due to limited height of said spell...the rain would likely condense and fall only a few hundred feet at most, depending on the spell...thus you might also expect fog or extremely low-lying clouds).

[The Ravensong]

Please, Please name yourself Nuk'Tuk, The Hero of the South
With that out of the way; here are some spells that might catch your attention
Extract Water Elemental Sor/Wiz/Dru 6 - Spell Compendium 1d6/level untyped damage (fort half). If this kills the enemy you get a free water elemental of your victim's size.
Rogue Wave - Sor/Wiz/Clr4 Dru3 - Dragon 314- 1d6/2 levels bludgeoning damage (fort half). Knocked prone on failed save, more powerful and save penalties if cast in water
Kelgore's Grave Mist - Sor/Wiz2 - 1d6 cold/round +fatigue no save. A second casting stacks the damage in the aoe and causes exhaustion!
Conjure Ice Beast I-IX- Cleric/Druid - Lets you make construct versions of monsters from SNA and SM lists with new abilities (I particularly like mixing the no-save frost aura with Kelgore's Grave Mist as a Cleric with the Divine Magician alternate class feature)
Burning Blood - Sorc/Wiz4 - 1d8acid+1d8fire 1 round/level. Fort save ignores damage for that round, failure limits them to a single move action that round.

My suggestion build wise would be to go with suprise! Divine Magician Cleric (Which lets you give up a domain in exchange for the ability to cherry pick a few spells from the sor/wiz list). Grab Southern Magician as a feat (Hero of the South!) Then grab Kelgore's Grave Mist as your second level spell.
I've always liked the Winterhaunt prestige class for Hydromancers because waterbending is awesome and it's often easier to get mileage out of frost magic... but it also gives you a boost to damage from cold spells of up to +3d6
Black Lore of Moil metamagic feat lets you drop stacking AoEs that do 4d6cold+2d6negative damage/round, along with fatigue (-2 str and dex, no running or charging).
Fell Weaken adds another -4 str penalty to any damage dealing spell for +1 spell slot (and grave mist is already a steal at level 2)
Combining a Fell Weakened Kelgore's Grave Mist with Conjured Ice Beast I Wolves with the frost aura gives you another no save 1d6 cold damage and a mini-meatshield to attack and trip your enemies (who are suffering from -6 str and -2 dex)
Flash Frost Spell gives an extra 2cold/spell level (+4/round for Grave Mist) and the spells area generates a dc10 balance check to move dc20 to run/charge. +1 Spell level and helps to keep your victims locked in the AoE.
Elemental Substitution: Acid/Electricity. Because eventually the DM is going to get tired of your shenanigans, or the villains are going to give themselves cold immunity/resistance. Kelgore's Acidic/Electrifying Mist would be a terrible sight for them to behold.
Snowcasting Gives any spell the cold descriptor, so you can flash frost anything with an area of effect, like obscuring mist, or darkness, or glitterdust (Blinded and stumbling all over the place? Yes please), or exploding rune field (That'd just be silly).
Southern Magician lets you cast arcane spells as divine and divine spells as arcane... which lets you qualify for...
Arcane Thesis! This lowers the spell slot cost of adding metamagic feats to spells. So you can have your Snowcasted Fell Weakening Flash Frost Kelgore's Acid Mist of the Black Moil wreaking havoc on your enemies and only use up a level 2 spell slot.

[Diovid]

Aside from the Wavekeeper and Sea Witch mentioned above, Lord of Tides (Sandstorm) also fits the concept.