My first Tiefling. Design questions for spell progression issues.

[Silentline]

This is my first tiefling character and I went all HP Lovecraft with it to terrify even myself. But I'm having a bit of trouble with the spell progression after the 9th level of spells for each prestige class.

This is the character I'm working with.

Character Theme: Sovereign: Control (Aether)

Always got a theme song to each character. 🙃 Because it's so immersive.

Normally I play an average fighter or a simple druid. But I was challenged to bring something I never play to the table so I did.

Summary: An enigma to my party. Rescued as a child from beyond the 666th layer of the abyss by the planeswalkers guild she's the progany of a devil and a demon Tiefling.. In her bloodline exists something much darker and deeper.. making the other PC's kind of uneasy at first which turned to awe when the young witch resurrected the parties slain half-dragon paladin from his grave site restored to perfect health.

Merothelllrruncnu
(Mir'Ruth'(exhale when you say it) Ahlll'Rr'(clear your throat as you say) Unk' Nu). Nicknamed: Mad Erideth

Main-Form: A statuesque dark purple Tiefling most alien with reflective pupiless black eyes that blink sideways in adjustment to bright light.. her joints a deep pearlecent. Never ashamed of her bare appearance she Dawn's 3 sets of horn types upon her head, two sets of breast one over the other, and what looks likes like random writhing just under her skin as though there were a creature inside her adjusting to get confortable. Her shark like smile is as unnerving as her attempt to conversate because she speaks with 4 different pitch voices as one. When first rescued she struggled to break evils hold on her mind and succeeded but it's a daily struggle to remain neutral alignment. Her attire us that of a swamp witch with all gear fire/acid proof. She's a legend among the planeswalkers guild as a guide to the far reaches of the abyss, the nine hells, and even short trips through far realm travels.

Alternate form: A creature from the far realms long thought forgotten.. she's something that he mind tries to seclude to nightmares.. Eyes all about her body, multiple limbs, tentacles, mouths with teeth on the outside and inside.. it's hard to distinguish what appendage is what.

Nuetral Female"Pseudonatural" Tiefling
Beholder mage 1 (Arcane hands), Human Paragon 3 (Able learner, +2 intelligence), Fighter 1 (Improved initiative), Ur-Priest 1, mystic theurge 8. Intelligence 25, Elder evil servitude feats before rebelling but still remain despite alignment shift - Willing deformity, Deformity (Madness)."hence why she's call Mad Erideth as she's not all the way there. But her mind seems able to ignore mental affect because of it."

Traits: Aggressive x2 (-2 ac +4 initiative)
Flaws: Noncombatant (-4 melee attack roles.. +2 additional feats)

Feats that make it happen: Human heritage (May use human only magical items etc ), Old blood (True Beholder - for all intents and purposes she also counts as a true beholder including prestige classes), Lost tradition (may use Intelligence as Ur-Priest main stat)..

/So I guess it's true. Beauty is in the eye of the beholder. 🤭/

Feats that she's yet to achieve.. Demon mastery and Extract demonic essence.

Special storyline background plot hook: Still born (died) and resurrected through a terrible ritual clouding her mind to the service of an elder evil.

Books of reference-
-Complete Divine
(Guide to all things divine)
-Unearthed Arcana
-Races of renown
(Bastards and Bloodlines)
-Races of Destiny
(Guide book to humans)
-Lords of Madness
(The book of Aberrations)
-Players hand book
-Fiendish codex 1
-Fiendish codex 2
-Planer handbook
-Elder evils
-Book of Vile darkness
-Pretty much any book with a useful spell arcane or Divine.

Im only level 15 and have a spell book that can rival an entire community of casters.
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Now the questions.

Can I continue to do mystic theurge to achieve 2 spell lists in epic levels before lv. 20 or am I banned from lv 10 spell use untill I'm level 21?

Is it even possible to have epic level beholder mage and Ur-Priest spells into epics like arcane Archer and assassin?

I do know that some classes simply stop at 5 or 10 but some can go to epics. So should I be forced to discontinue mystic theurge what should I use as filler? I've pondered Geomancer or Hexer to give it more of a "Creepy Swamp Witch" feel while mixing and matching variables. But I don't want to gimp it. Maybe something better I'm not noticing to help the concept.

Do you think the DM have will develop the epic progression needed or is it already listed somewhere? Because I didn't see it in the epic lv. Handbook. Maybe I overlooked it somewhere.

Answers? Questions to help answer? Additional Comments? Tips? Tactics? Complements of any kind? Donations in the form of cookies? Additional counter beholder puns? All would be very much appreciated.

[Anthrowhale]

Mechanically, Beholder mage requires eyestalks with magic rays to sacrifice---unclear on how you are getting that.

More generally, spells don't advance beyond the end of the table for each class, even in epic (caster level can advance).

[KillianHawkeye]

You can't take the epic version of a class or prestige class until you reach epic levels.

[Telonius]

For casting an Epic spell, you need the Epic Spellcasting feat in order to do it. That feat requires 24 ranks in Spellcraft, so is out of range until Level 21.

There are a very few ways to get around this. Primary Contact from Cityscape lets you exceed the regular limit; so does the Laborious Training feat from "Legacy of the Blood" (a Ravenloft book - it's published under "Sword & Sorcery," but has the Official WotC Licensed Product seal, so I believe it counts as first party). Other methods I've heard talked about are very cheesy (getting and curing lycanthropy, polymorph cheese involving Dusk Giants, and otherwise instantly getting large numbers of extra hit dice to allow qualification).

[Silentline]

The characters alternate form possesses an inhuman amount of eyestalks. I will have to consult my DM for exactly how.many she would have in that form.

Her central nervous system in the alternate form is identical to the beholder though without rays. I was told I only had to sacrifice them if I actually had them considering it's general anatomy explanation she qualifies for the process of the beholders arcane class whether justification through a more than potent bloodline to satisfy the characters innate power like a sorcerer or even gather it like a wizard. And since having rays wasn't stated as a class requirement in either case I was allowed to qualify for the class.

Kind of like the requirement of putting out the anti-magic eye to cast spells. The character never had it to begin with to permit interference or worry about sacrificing it in the first place. The rest is just typical slightly more complex casting that she is able to grasp through qualification of being considered a true beholder.

She can cast spells and perform magic using the eyes as more of a spell storage which I was told can be destroyed along with it the spells stored if struck with enough damage. As for projecting simple non-spell dependant beholder rays. No she can't do that. In fact I was told she could never do that even though she's considered a true beholder for the sake of arguement. If the prestige class doesn't allow her the rays naturally then it's not possible and spells are to be cast without touch attacks unless the spell requires it. I was also td she could use mage hand in either form as well. The only way she can cast a ray is by certain spells such as ray of enfeeblement and the like as a stored spell.

I pressed the what if idea of an implant for each eyestalk but she'd only get 1 ray/per day out of each individual eye per implant which is kinda cool but also expensive and unconventional. Besides she would have to sacrifice it in order to cast spells anyway.

The DMs trade off of to having to slip into an alternate form to cast arcane spells of that Calibur through eyestalks used as spell stores to support a rather creepy concept seemed pretty adequate.

I was told she can't recycle magic by simply looking at it or use the same scroll for months on end and she also isn't boyant as the feat simply goes only so far. I was told when a scroll is used by her it's 1 time use as normal. Any spell she casts is gone for the day as standard until restored normally with rest. Where a beholder has a limitless amount of spells known she is still bound by the rules of core statting because her tiefling brain is No where near as big (according to beholder anatomy size matters as well as having dweomerlobes) in comparison to the beholder despite her 25 intelligence to it's casual 17. I brought up the idea of, "what if she stays in that form can she learn limitless spells because her brain anatomy shifts larger and has dweomerlobes" and I was told, "sure and the moment she reverts to normal form she'd lose all the spells over the amount her intelligence granted wasting all your funds and time." What scared me the most is when the DM smiled and said, "and I get to pick which spells remain. And I say Starting at your cantrips up are the ones you hold onto first and foremost because they are the easiest to remember." So I dropped that idea like a hot potato.
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Right now I'm worried about what class to pick up for those last levels before 21. I don't want them to be just filler.

I'm interested in the wayfarer class to improve party planer travel which is my characters job as a planer guide. But that still leaves unused levels.

You guys are pure genius! I'm going to try to use those methods. I don't want to waste any potential. But lycanthropy is going a bit too far. The DM is looking for any reason to revoke my neutral alignment so I have to stick to the boundries of.the character. I'm already pushing it with this entire concept. 🙃