So i have a question that is probably been discussed tons.
Can a necromancer, animate enough undead to equal or be greater then his/her CR or level using mythic and any special feats? (If read correctly)
There is no limit on the number of undead creatures a spellcaster can create, just on how many they can control.
Through the use of the Animate Dead spell, any spellcaster can create and control up 4 HD of undead per caster level. So if you've got caster level 10 then you can control up to 40 HD of undead creatures in this fashion. You can increase this amount through items or feats that increase your caster level. There's also the Juju Mystery Oracle which can increase the total number ocntrolled to 5 HD of undead per caster level.
The Command Undead spell is another common method of controlling mindless undead. There is no limit on the number of undead you can control in this fashion, provided you recast it before the duration runs out.
The Command Undead feat (which is completely different from the spell) is a less reliable option that can control only 1 HD of undead per effective Cleric level. So if you gained the Command Undead ability through the Necromancy Wizard school then you could control 1 HD of undead per Wizard level. Due to the small cap and the saving throw this method allows it is not favored.
Animate? Oh yeah.
Control? That's a bit trickier. (Though still pretty easy)
With mythic, it's really easy. Just take Mythic Control Undead, control a vampire/other spawn-creating undead, and have a giant chain of undead all under your control (just be careful to never lose your command over the progenitor).
Using either a Wordcaster oracle/cleric or just taking the Experimental Spellcaster feat, it's possible to get a close-range, no-component Animate Dead equivalent as a 2nd level spell. Spamming that can give you up to 12 HD of undead at level 3. If those 12 HD are used in controlling 4 zombie leopards, that gives you 4 CR 1 creatures, which is equivalent to a CR 5 encounter- while you're level 3.
What i am meaning to accomplish is in a single casting. :)
Hmmm.... Now that's trickier.
The biggest strength of necromancers is their ability to make up a bunch of minions before the conflict, potentially saving even the spell slots needed. What level range are we looking at? That might change things a bit, but, to my knowledge: No. With the possible exception of level 3, if you're facing a 6-HD small or medium monster, and it dies, you could reanimate it into a 7 HD zombie, with a CR of 3.
Hmmm...
Well, with one casting of Undeath at CL 3, you could reanimate a zombie Giant Owl, which, as a Huge animal, would have an adjusted CR of 4. (This would also work with any other 6 HD Huge or bigger creature)
At CL 5, if you could reanimate a Titan Centipede (a CR 9 creature), which, as a colossal creature, would have a total of 20 HD, and a CR of 7.
Ok lets talk class levels... she would have 4 mythic teirs. Lvl 15 wizard damphir Cruoromancer with the favored class option for damhir, spell focus, greater spell focus, control undead, and undead master. Have fun :)
What i am meaning to accomplish is in a single casting. :)
Under the effect of the Desecrate spell you can create 4 HD of undead per caster level with a single casting of Animate Dead.
Ok lets talk class levels... she would have 4 mythic teirs. Lvl 15 wizard damphir Cruoromancer with the favored class option for damhir, spell focus, greater spell focus, control undead, and undead master. Have fun :)
These are the bonuses I was able to come up with:
Favored Class Bonus = +3 caster level for necromancy spells
Undead Master feat = +4 caster level to animate dead
Spell Specialization feat = +2 caster level to animate dead
Wild Arcana (mythic ability) = +2 caster level
Mythic Animate Dead = +4 caster level
That takes us to caster level 30. You could get a few extra CL on top of this, but that requires either using more obscure sources or very expensive items (Orange Prism Ioun Stone) and we're well past the point of diminishing returns anyways. That's 120 HD worth of undead in a single casting.