Black Mage : A few questions

[Seera1024]

While you could Xenoglossy, I would actually Despair first.

A good standard rotation at level 90 is:

Blizzard 3
Blizzard 4
Thunder 3 or Xenoglossy [a filler spell to ensure you fill mana before swapping back to Astral Fire]
Paradox [if you have it]

Fire 3 [will be a fast cast if coming off of Umbral Ice]
Fire 4
Fire 4
Fire 4 - you should be about out of time here
Paradox/Fire 1 [This should ideally be paradox, but either paradox or fire 1 will refresh your timer here, if you happen to have a Fire 3 proc sitting around, this is also a good place to use it]
Fire 4
Fire 4
Fire 4 - you should be both about out of time and out of mana
Despair - will refresh your timer AND deplete your mana, but Blizzard 3 while in Astral Fire costs 0 mana.

Start back over at Blizzard 3.

You should have enough time in Astral Fire phase to cast one additional spell during the time period. But remember that unless you have a Fire 3 proc or can immediately cast either Triplecast or Swiftcast beforehand, you can't attack and move and refresh your timer. If you can't consistently get 3 Fire 4's off, drop down to 2 Fire 4's.

Here's a video I was given recently when I was looking for rotation improvement as my group of friends just recently started a static:

https://www.youtube.com/watch?v=oitfdOPiqpw

There's more in there than you will need, I know there were sections there that I decided I wasn't going to bother with currently as they are more advanced. But it's got answers for the majority of the off global cooldowns and where and how to fit them into your rotation.

For my filler, I use Thunder 3 with Sharpcast having been used between Blizzard 3 and Blizzard 4 while waiting for the GCD to refresh. This gives me an instant cast thunder in case I need to suddenly move in fire phase. Then I can pop Thunder 3, then immediately triple cast or swiftcast in order to continue DPS'ing while doing any necessary movement.

[JacobNewblood]

1- First of all, I regularly see rotations that start with ice magic. In my head, ice magic is good for gaining mana. Since at the start of a rotation I still haven't used any mana, why start a rotation with ice?

Ideally you won't start with ice Anymore, You can start with sharpcast into a precast fire 3, with thunder and some fire 4s, then refresh with fire 1, and fire 4s, then dispare and manafront to get another fire 4 and dispair in then switch to ice, using your polyglots and thunder clouds in between to weave in leylines or tripplecast.

2- I don't understand the Umbral soul spell at all. (level 76) I may well reread the spell, but I don't see the point. Can someone explain it to me? all

TLDR you spam it in ice mode between mob pulls or in downtime. this is to keep your timer running and polyglot ticker ticking

3- Some spells use all mana. I imagine the goal when using one of these spells is to use manafont afterward?

idealy yes, if you have umbral hearts the ALL mana spells only cost half mana for the first cast, this is great for you can get extra fire IV and dispair in your ST rotation and a 3rd flare in your aoe roatation.

4- Fire IV has 300 firepower. Despair has 340 firepower, but it uses all mana. Is it really a benefit to use Despair for 40 more?

Yes for by All = minimum of 800, therefore less mana cost so you can use more fire 4s to a lower threshold of mana and still cast a fire spell that resets your timer and does damage.

[RiversideGuy]

Ha, that's kinda sorta exactly what I do... B3, B4, T3, F3, F4, F4, F4... BUT you say F1 to reset the timer, BUT pretty sure I am just about out a mana at that point... maybe I'm out of it, but I don't recall seeing that F3 being a fast cast... I'll hit a dummy and pay attention.

[Stepjam]

Ha, that's kinda sorta exactly what I do... B3, B4, T3, F3, F4, F4, F4... BUT you say F1 to reset the timer, BUT pretty sure I am just about out a mana at that point... maybe I'm out of it, but I don't recall seeing that F3 being a fast cast... I'll hit a dummy and pay attention.

The hardcasting fire 3 that jacobnewblood mentioned is for the opener. Midfight you only hardcast F3 to transition from ice phase to fire phase.

Also if you go into fire phase with full MP, you'll have just enough to cast F4 three times, F1, F4 3 more times then despair. If you are running out of MP by Fire 1, that likely means you are either leaving ice phase too fast or are forgetting to use blizz4.

[RiversideGuy]

Ah, NIOW I see it... I made the wrong assumption that lacking umbral hearts, one could not cast a FIV. THEN I see that Paradox does replace my F1 button. Just tried it on a dummy, 3 FIVs, Paradox, timer refreshes, no umbral hearts on my gauge, BUT I can cast a few more F4s. One of these days I may eeek more than 50% of it's potential from this job!