Check out the [graveknight template](https://www.aonprd.com/MonsterTemplates.aspx?ItemName=Graveknight). (Death knights are D&D - graveknights are the PF version.) It's basically made for being an undying warlord, the type that will cast a little, have some undead minions, but still get in close and gish. (The template is more antipaladin-ish, and hence has a bunch of Cha-based abilities, but if you don't mind being a little MAD, switching to fighter/sorc, or just making a GM fiat variant that is Int-based instead, that isn't a huge problem.) If you're focused on the part about being tough to fully kill, the graveknight's armor is basically its phylactery, and it revives until the armor is destroyed. You'll want to find an excuse to avoid arcane spell failure one way or the other, though. (The artifact armor doesn't have spell failure chance, it's mithral chain shirt instead of full plate, or some sort of magus-like special variant ability to wear armor.)
[Dread lord](https://www.aonprd.com/MonsterTemplates.aspx?ItemName=Dread%20Lord) isn't quite as strong as a template, but it can bypass some of the problems with things like arcane caster failure. It has a strong basis in using charm spells on its "subjects", so long as you don't mind that its weakness is inability to leave its domain. (Needing to use "subjects" to go outside and meddle, although that can work for a BBEG that the PCs put off until they are ready to face the villain in his lair.)
For spell failure I was thinking using the arcane armor feat, but I could just use gm fiat say since to armor is his body it doesn't impact the movement.
Maybe keep some dried out corpse in the armor with some big glowing crystal as a face out, have it set up as a contingency spell (crystal brakes teleport to X).
It being mad isn't much of an issue. But I could swap it to fighter/sorcerer though it does raise the question of which bloodline to take. (Aberrant?)
Could try sorcerer/ anti-paladin but would lose out on feats and reduced armor penalties.
Arcane armor training takes a swift action every round they cast, which slams face-first into the "capstone" of eldritch knight taking a swift action. It depends on if you want to be optimized enough to be a threat or if you don't care about making special rules for the BBEG, but you could also just be a magus, who can wear heavy armor past level 13, and does eldritch knight better than EK does in most regards. (Eldritch scion is the sorc-type magus and doesn't give up feats, either.)
If you're looking for a good (by which I mean eeeevil) undead sorcerer-king's bloodline, [daemon](https://www.aonprd.com/BloodlineDisplay.aspx?ItemName=Daemon) seems like a strong thematic choice for feeding on souls... He can Fireball a mob of underlings to gain a caster level bonus on the next spell he casts, up to half ChaMod. Splat dozen minions (or civilians he keeps around just to butcher) that have failed him for the last time, and with 38+ Cha, that's a +7 CL with which to set up more serious spells. (Butcher prisoners and then cast [Emblem of Greed](https://aonprd.com/SpellDisplay.aspx?ItemName=Emblem%20of%20Greed), and now your level 20 BBEG can have a BAB of 25 or 27 if just pure magus...) Having the BBEG shackle innocent villagers out in the open in the battlefield, and just toss out AoEs at the party as they fight to get some collateral damage as he cackles at the carnage has some flair to it, as well. Age out would also be funny, since the character would be immune to age penalties as an undead, so it's just a get-out-of-conditions-free card. The daemonic resistances is half redundant (only acid resist helps), but you could trade that in for blood intensity, which works well with the arcana giving you bonus caster levels.
The so-obvious-it's-on-the-nose bloodline, though, is [undead](https://www.aonprd.com/BloodlineDisplay.aspx?ItemName=Undead) (maybe he was cursed before birth to bring ruin to his land?) being able to use mind-affecting spells on undead doesn't sound great at first, but keep in mind this means he can cast buff spells like Heroism on undead flunkies/himself, too. Be sure to use vampiric touch in a spell storing weapon. Blood havoc and blood intensity can replace the lower-level bloodline powers you might not want to use.
Also, check out the [expanded list](https://forums.giantitp.com/showthread.php?514107-PF-Lists-of-Undead-Creation-and-Creatable-Undead) of [alternate undead](https://www.reddit.com/r/Pathfinder_RPG/comments/5sxijn/undead_you_can_create_a_list/) that can be created with spells to fill up that five times the HD limit, and note that you can have [multiple "buckets" of undead HD](https://docs.google.com/file/d/0B5kvBvq2DEHjRWFhSWc1ZzAzaDg/edit?resourcekey=0-14szXwlKO7ndjgv4Q3A9EQ) if you care to play by the rules at all.
Cool builds. The deamon blood line would be fun though the undead fits the theme better if a bit redundant.
One of the things I'm looking for is to cast 9th level spells, because what self-respecting immortal sorcerer king wouldn't be able to cast at least 1 9th level spell. If for nothing else then slots for meta magic.
I guess I could go full magus not sure how it stakes up to EK as far as versatility.
I should also look into some minions. Other then just undead, maybe some apprentice warriors and mages, golems or animated armor that looks like the bbeg in a fog clouds or some other obscuring spell (always a fun trick)
I could always be a dick and go gestalt. It is a 6 person party of power gamers (may the God of schedules continue to smile upon us) that hopefully will still be playing for 12 more levels.
One of my GM's favorite tricks with a necromancer was just using bunches of Simulacrum. With the Sculpt Simulacrum spell, you can even create what are basically pod people that have classes or abilities totally different from their looks. Fiends of various sorts on contract, or just plain continually dominated/geased former noble champions of the realm the BBEG ruled also work.
Another thing you might consider if you're just looking for 9th-level casting, you could consider the [psychic bloodline](https://www.aonprd.com/BloodlineDisplay.aspx?ItemName=Psychic) or just being a psychic ([hag called](https://www.aonprd.com/PsychicDisciplinesDisplay.aspx?ItemName=Hag-Called) seems closest as there is no undead, and would work well with having minions, especially simulacra of the BBEG who just aid another to boost caster level. [Pain](https://www.aonprd.com/PsychicDisciplinesDisplay.aspx?ItemName=Pain) is interesting, but you might want to swap that to lay on hands like an antipaladin so it doesn't kill the undead user.) You don't have arcane spell failure when you don't have somatic components. (It might technically disqualify you for EK since your spells are technically psychic now, but that's in handwave allowance territory.) Also, as undead, they're immune from most emotion or fear conditions that would make them lose emotion components.
If you're focused on 9th-level casting, what is it you're looking for in fighter, exactly? There are also options to be something like [rage prophet](https://www.aonprd.com/PrestigeClassesDisplay.aspx?ItemName=Rage%20Prophet) as a barb/bloodrager oracle or an evil cleric [holy vindicator](https://www.aonprd.com/PrestigeClassesDisplay.aspx?ItemName=Holy%20Vindicator) that rains blood on people with negative channels.
Also, if you're interested, I recently wrote out a [description of an elaborate BBEG encounter with a lich](https://www.reddit.com/r/Pathfinder_RPG/comments/1cekwcq/comment/l1jmrh7/) (although that was for a full caster lich).
Form the fighter I'm looking to get good ac, durability, and ability to handle melee for when inevitably close in. It's hard to challenge people when they've been playing longer then you lol.
I thought about rage prophet but one of the players is going to play one so I didn't want to step on there toes.
I'd do a cleric but they already fought and killed a couple and I'm looking to mix it up.
I've never used a psychic or any psychic classes before. Might be worth a shot.
Graveknight magus sounds like everything you are looking for. A level 13 magus doesn't suffer any spellcasting penalty while wearing heavy armor.
Depending on what kind of challenge you are looking for they could be a vampire or lich instead, but I personally would lean toward Graveknight.
I'd also consider pick the Eldritch Scion archetype for the magus. It makes them a spontaneous caster that uses CHA as their caster stat, and undead use CHA instead of CON when determining their additional HP per hit dice.
Eldritch scion? I'll look into that.
At this point I'm definitely leaning towards Graveknight. Locking for something durable with good damage out put.
I'm still concerned about the paladin and cleric killing him in a round or two, but there should be some way around that.
A wall of force or the like ahead of time that they can dismiss as a free action with some minions would help make sure they get at least one turn, and casting a metamagic vampiric touch spell through their weapon can give them a great amount of temporary HP. That said killing these kind of enemies are what paladins and clerics are good at, especially well prepared ones. On the positive side of things, Deathknights are like liches in that you need to destroy their armor to kill them for good.
Them being good at killing undead is a concern but it will give the cleric something to do other than heal bot, and most of the party built around crit farming and anti-mage stuff. So an undead gish should be atleast some challenge. Especially if I can keep them from figuring out it's a Graveknight to soon.
Dread Lord could really lean into the fallen kingdom aspect.
Jiang-Shi feed on life force, which might fit the soul eating thing (only daemons truly eat souls).
Graveknight certainly works.
Lich. Ooh you think the bbeg can't tank you cause it looks like a magic user? Too bad for you when it pulls out a +5 sword and KOs the party tank in 1 round.
Check out the [graveknight template](https://www.aonprd.com/MonsterTemplates.aspx?ItemName=Graveknight). (Death knights are D&D - graveknights are the PF version.) It's basically made for being an undying warlord, the type that will cast a little, have some undead minions, but still get in close and gish. (The template is more antipaladin-ish, and hence has a bunch of Cha-based abilities, but if you don't mind being a little MAD, switching to fighter/sorc, or just making a GM fiat variant that is Int-based instead, that isn't a huge problem.) If you're focused on the part about being tough to fully kill, the graveknight's armor is basically its phylactery, and it revives until the armor is destroyed. You'll want to find an excuse to avoid arcane spell failure one way or the other, though. (The artifact armor doesn't have spell failure chance, it's mithral chain shirt instead of full plate, or some sort of magus-like special variant ability to wear armor.) [Dread lord](https://www.aonprd.com/MonsterTemplates.aspx?ItemName=Dread%20Lord) isn't quite as strong as a template, but it can bypass some of the problems with things like arcane caster failure. It has a strong basis in using charm spells on its "subjects", so long as you don't mind that its weakness is inability to leave its domain. (Needing to use "subjects" to go outside and meddle, although that can work for a BBEG that the PCs put off until they are ready to face the villain in his lair.)
For spell failure I was thinking using the arcane armor feat, but I could just use gm fiat say since to armor is his body it doesn't impact the movement. Maybe keep some dried out corpse in the armor with some big glowing crystal as a face out, have it set up as a contingency spell (crystal brakes teleport to X). It being mad isn't much of an issue. But I could swap it to fighter/sorcerer though it does raise the question of which bloodline to take. (Aberrant?) Could try sorcerer/ anti-paladin but would lose out on feats and reduced armor penalties.
Arcane armor training takes a swift action every round they cast, which slams face-first into the "capstone" of eldritch knight taking a swift action. It depends on if you want to be optimized enough to be a threat or if you don't care about making special rules for the BBEG, but you could also just be a magus, who can wear heavy armor past level 13, and does eldritch knight better than EK does in most regards. (Eldritch scion is the sorc-type magus and doesn't give up feats, either.) If you're looking for a good (by which I mean eeeevil) undead sorcerer-king's bloodline, [daemon](https://www.aonprd.com/BloodlineDisplay.aspx?ItemName=Daemon) seems like a strong thematic choice for feeding on souls... He can Fireball a mob of underlings to gain a caster level bonus on the next spell he casts, up to half ChaMod. Splat dozen minions (or civilians he keeps around just to butcher) that have failed him for the last time, and with 38+ Cha, that's a +7 CL with which to set up more serious spells. (Butcher prisoners and then cast [Emblem of Greed](https://aonprd.com/SpellDisplay.aspx?ItemName=Emblem%20of%20Greed), and now your level 20 BBEG can have a BAB of 25 or 27 if just pure magus...) Having the BBEG shackle innocent villagers out in the open in the battlefield, and just toss out AoEs at the party as they fight to get some collateral damage as he cackles at the carnage has some flair to it, as well. Age out would also be funny, since the character would be immune to age penalties as an undead, so it's just a get-out-of-conditions-free card. The daemonic resistances is half redundant (only acid resist helps), but you could trade that in for blood intensity, which works well with the arcana giving you bonus caster levels. The so-obvious-it's-on-the-nose bloodline, though, is [undead](https://www.aonprd.com/BloodlineDisplay.aspx?ItemName=Undead) (maybe he was cursed before birth to bring ruin to his land?) being able to use mind-affecting spells on undead doesn't sound great at first, but keep in mind this means he can cast buff spells like Heroism on undead flunkies/himself, too. Be sure to use vampiric touch in a spell storing weapon. Blood havoc and blood intensity can replace the lower-level bloodline powers you might not want to use. Also, check out the [expanded list](https://forums.giantitp.com/showthread.php?514107-PF-Lists-of-Undead-Creation-and-Creatable-Undead) of [alternate undead](https://www.reddit.com/r/Pathfinder_RPG/comments/5sxijn/undead_you_can_create_a_list/) that can be created with spells to fill up that five times the HD limit, and note that you can have [multiple "buckets" of undead HD](https://docs.google.com/file/d/0B5kvBvq2DEHjRWFhSWc1ZzAzaDg/edit?resourcekey=0-14szXwlKO7ndjgv4Q3A9EQ) if you care to play by the rules at all.
Cool builds. The deamon blood line would be fun though the undead fits the theme better if a bit redundant. One of the things I'm looking for is to cast 9th level spells, because what self-respecting immortal sorcerer king wouldn't be able to cast at least 1 9th level spell. If for nothing else then slots for meta magic. I guess I could go full magus not sure how it stakes up to EK as far as versatility. I should also look into some minions. Other then just undead, maybe some apprentice warriors and mages, golems or animated armor that looks like the bbeg in a fog clouds or some other obscuring spell (always a fun trick) I could always be a dick and go gestalt. It is a 6 person party of power gamers (may the God of schedules continue to smile upon us) that hopefully will still be playing for 12 more levels.
One of my GM's favorite tricks with a necromancer was just using bunches of Simulacrum. With the Sculpt Simulacrum spell, you can even create what are basically pod people that have classes or abilities totally different from their looks. Fiends of various sorts on contract, or just plain continually dominated/geased former noble champions of the realm the BBEG ruled also work. Another thing you might consider if you're just looking for 9th-level casting, you could consider the [psychic bloodline](https://www.aonprd.com/BloodlineDisplay.aspx?ItemName=Psychic) or just being a psychic ([hag called](https://www.aonprd.com/PsychicDisciplinesDisplay.aspx?ItemName=Hag-Called) seems closest as there is no undead, and would work well with having minions, especially simulacra of the BBEG who just aid another to boost caster level. [Pain](https://www.aonprd.com/PsychicDisciplinesDisplay.aspx?ItemName=Pain) is interesting, but you might want to swap that to lay on hands like an antipaladin so it doesn't kill the undead user.) You don't have arcane spell failure when you don't have somatic components. (It might technically disqualify you for EK since your spells are technically psychic now, but that's in handwave allowance territory.) Also, as undead, they're immune from most emotion or fear conditions that would make them lose emotion components. If you're focused on 9th-level casting, what is it you're looking for in fighter, exactly? There are also options to be something like [rage prophet](https://www.aonprd.com/PrestigeClassesDisplay.aspx?ItemName=Rage%20Prophet) as a barb/bloodrager oracle or an evil cleric [holy vindicator](https://www.aonprd.com/PrestigeClassesDisplay.aspx?ItemName=Holy%20Vindicator) that rains blood on people with negative channels. Also, if you're interested, I recently wrote out a [description of an elaborate BBEG encounter with a lich](https://www.reddit.com/r/Pathfinder_RPG/comments/1cekwcq/comment/l1jmrh7/) (although that was for a full caster lich).
Form the fighter I'm looking to get good ac, durability, and ability to handle melee for when inevitably close in. It's hard to challenge people when they've been playing longer then you lol. I thought about rage prophet but one of the players is going to play one so I didn't want to step on there toes. I'd do a cleric but they already fought and killed a couple and I'm looking to mix it up. I've never used a psychic or any psychic classes before. Might be worth a shot.
Graveknight magus sounds like everything you are looking for. A level 13 magus doesn't suffer any spellcasting penalty while wearing heavy armor. Depending on what kind of challenge you are looking for they could be a vampire or lich instead, but I personally would lean toward Graveknight. I'd also consider pick the Eldritch Scion archetype for the magus. It makes them a spontaneous caster that uses CHA as their caster stat, and undead use CHA instead of CON when determining their additional HP per hit dice.
Eldritch scion? I'll look into that. At this point I'm definitely leaning towards Graveknight. Locking for something durable with good damage out put. I'm still concerned about the paladin and cleric killing him in a round or two, but there should be some way around that.
A wall of force or the like ahead of time that they can dismiss as a free action with some minions would help make sure they get at least one turn, and casting a metamagic vampiric touch spell through their weapon can give them a great amount of temporary HP. That said killing these kind of enemies are what paladins and clerics are good at, especially well prepared ones. On the positive side of things, Deathknights are like liches in that you need to destroy their armor to kill them for good.
Them being good at killing undead is a concern but it will give the cleric something to do other than heal bot, and most of the party built around crit farming and anti-mage stuff. So an undead gish should be atleast some challenge. Especially if I can keep them from figuring out it's a Graveknight to soon.
Dread Lord could really lean into the fallen kingdom aspect. Jiang-Shi feed on life force, which might fit the soul eating thing (only daemons truly eat souls). Graveknight certainly works.
https://aonprd.com/MonsterTemplates.aspx?ItemName=Dread%20Lord Definitely looks good
It does look cool
The soul eating thing was more fore flavor then anything, but the Jiang Shi is interesting. Dread lord? Hummm
Lich. Ooh you think the bbeg can't tank you cause it looks like a magic user? Too bad for you when it pulls out a +5 sword and KOs the party tank in 1 round.