two said:
uh, seriously --
For 3 9th level spells -- forget about Wish. Like, seriously. Instead --
I would GATE in 3 different "helpers" to, well, help destroy the enemy army.
Particularly effective would be some high level monster that can create shadows or something along those lines. It turns 10 enemy units into 10 shadows, which then (along with the gated in big baddie) turns another 10 enemy units into 10 shadows, which then... etc.
Or something that turns the enemy into zombies, or something like that. It's obviously much better to use the enemy army against itself instead of just, well, killing them.
If you have a week or so, a battle of attrition vs. 3 high CR enemies with lots of spell-like abilities should be able to a HUGE amount of damage to any army. The summoned creates can just retreat for a while when real danger appears, after all.
There's a catch; Gated creatures can only be at-will controlled for a number of rounds equal to your caster level, and that takes concentration, so you can only do one at a time. You might find your gated critters will be a tad annoyed with you after that. If you can throw lower-level spells around, though, you might consider Greater Planar Bindings - you make deals with them that can last for days, and can get up to 18 HD critters. A Sorceror of level 16 (minimum for Greater Planar Binding) can use GPB three times a day, and with the likelyhood of a very high charisma, can most likely control them for a while, too.
Of course, a level-12 Sorceror (minimum for Planar Binding) can bind a Noble Dijin or a normal Efreet three times a day and get three wishes out of each for no direct xp costs at all (Noble dijinn are Chaotic Good, Efreeti are Lawful Evil - choose your wishes accordingly).
two said:
Pick a high-end devil, a high-end demon, and a high-end undead?
So, the question is (I'm terrible at knowing monster abilities):
What sorts of monsters can turn their victems instantaneously (or near-instantaneously) into allies?
*are there any?*
Yep. Wights, Shadows, Wraiths, and Specters turn their victims into their own type, under the creator's control, 1d4 rounds after killing (well, draining something to 0, mostly - see individual entries) their victims. Shadows, Wraiths, and specters can be created under your control with Create Greater Undead, Clr 8, Death 8, Sor/Wiz 8. Ghouls and Ghasts (Create Undead, Clr 6, Death 6, Evil 6, Sor/Wiz 6) cause things that succumb to the disease they carry to rise as uncontrolled Ghouls or Ghasts (depending on the victims HD). Vampires can do similar (but takes 1d4 days after burial - they must be put into the ground, and there is a limit to the number of vampires spawn one vampire can control), and Mohrgs (Create Undead, Clr 6, Death 6, Evil 6, Sor/Wiz 6) turn things they kill into zombies 1d4 days later.
If you are evil, you can have lots of fun this way with Shapechange (Animal 9, Drd 9, Sor/Wiz 9; costly focus, but no material components, and you gain all the Su abilities of the assumed form; Create Spawn is usually Su, and most critters that Create Spawn end up under the control of their creator).