Time shifter

[Niab]

So...
If i wanted to make a time shifter .(flavor). My party is always hasted Mobs are slowed ..

What are the stacking sources of slow against Mobs?

Fear
Slow spell (description says AOE, Wiki says one target ??)
Ray of Exhaustion
Scare
Hold
Hypno
Gust of wind
Daze monster
Fascinate


Hamstring?

[Careall]

While useful for dealing with the trash, red and purple bosses will be immune to most of the effects you are looking for. For theme based flavor, you may want to consider taking Quicken Spell, just because.

For low levels - I'd say maybe good up to level 10 or so:
Hypnotism provides a nice quick area of effect 6-second, -3 Will debuff (no save) in addition to potentially stopping enemies. Combine this with Sonic Blast, and you can keep mobs in stop/go sort of turn-based mode, assuming you have plenty of mana.

For mid-levels, probably up to level 15:
Sleet Storm is a good solution except for the visibility problem... oh yeah, and the slipperiness that affects party members as well. However, Druids get both Sleet Storm and FOM, allowing them to slow enemies while keeping party members far less annoyed.

Solid Fog is a good 4th Level (7th caster level) spell to reduce movement and attack speed. There is no save or spell resistance.

While it may not be apparent, Cloud Kill, 5th Level (9th caster), can reduce enemies' Con in the cloud to 0, which stuns them for a few seconds. Get a stick or other weapon that can deal Con damage, and the stunning effect will occur a lot quicker.

For high-levels up to 20:
Mind Fog as a 5th Level spell (caster level 9) does a decent job of reducing Will saves, especially if you can support it with a high DC, and even Hypnotism from level 1 can give a -3 Will save to the Mind Fog.
Once the Mind Fog effect takes hold, your targets now have a -10 to Will saves. More than enough to land a good Hold Monster, Mass spell. However, if enemies happen to save against the Mind Fog, you will have to lure them out and then back in order to force a new Saving Throw. Lure them out, cast hypnotism, lure them back in, cast Hold Monster, Mass.


Some supporting spells you may want to consider:
Dispel Magic or similar. Enemies that can buff themselves may be able to resist your spells. Debuffing them with a Dispel Magic type spell can help.
Gust of Wind, but not why you may think. Casting AOE cloud spells can be annoying to party members. Cast Gust of Wind to clean up your messes.