There seems to be a confusion regarding his levels. Let me clear this for you all.
By DnD logic, he should be a way stronger than anyone else, and he is. But he is not most OP character in FR.
There are several points regarding Satoru and his build :
— His build revolves around role-playing.
— Such a build is useless for power gaming.
— But it opens a secret job class that put him above several character.
— He belongs to an undead race called Overlord, the ultimate form of undead.
— He has a job class that can kill anything, similar to Orcus' one time use [Last Word] spell.
— DD Levels represent the growth of a character in terms of job classes only, except dragons.
— Overlord Levels represent both racial and job developments which are necessary to take into account while understanding Satoru's presence in the FR. It is what Maruyama call the stages of evolution. Each level is equal to a new stage in the life of that entity.
Now, let's compare him to DD world.
In terms of numbers of spells, Raulothim knows over 400 spells. He is a CR 34 Gem Dragon.
On the other hand, Larloch knows all the "published spells" of Faerun. He is a CR 46 ancient lich. However, the total published spells are around 600 to almost 700. And thus lich has a memory to remember every single one of it.
Satoru has the same number of spells like Larloch, but he also memorized over 1000 spells that he xame across. Not only their names, but also knows how to counter them. So, you can guess his Intelligence score from this point. I know, a person's intelligence depends on many factors. And I am not saying that Larloch is not as smart as him. But in the DD logics, your Intelligence scores(if you are a necromancer wizard) represents your knowledge over Arcane lore and complicated rituals. With that in mind, Satoru is certainly above the likes of Raulothim, and equivalent to Larloch.
Both Satoru and Larloch are the hoarders of Netherese spells and artifacts. The thing is : Larloch has to learn the spell or prepare the spell before casting those Netherese spells, but Satoru can use them readily in battle. To me, they look comparable enough.
Wisdom score represent your Necromancer's attunement or familiarity with Death. Satoru came from a dystopia world where death and decay were commonplace and he himself has a job class called Ruler of Death.
Charisma represents the force of your personality over the souls or minds of others. You all know the results so, it is pretty obvious who takes the seat here.
These three are the main ability scores of Satoru in terms of DD. Let me know your thoughts over these.
— Now, let's talk about his race :
He is an Overlord, the highest tier of undead magic caster. His racial skills has many immunities and resistances that are as following :
Immunities : Electric, Ice, Acid, Disease, Death, Decay, Paralysis, Unholy, Negative, Sleep, Hunger, Thirst, Psychic, Energy Drain, etc.
Resistances : Turn(Undead domination powers), Necromancy, Slashing, Piercing, etc.
These are just his racial or innate powers. It sounds like a Demigod's immunities and resistances. With few extra protections that puts him easily rank 5 Demigod. He us certainly not a Lesser deity. But gosh, he seems like one.
His other two very special immunities are :
Immune to all physical attacks dealt by level 60 or below entities or items. Basically any DnD level 18 character are not dealing any damage on him.
Immune to all magical attacks upto 6th tier, which meant to 5th level spells. Titania's pact increased it upto 8th tier, which is 7th level in Dnd magic system. That Archfey is actually the strongest Archfey in all of DnD. She can pack enough power to threaten all of Intermediate Deities on her own, even Greater Deities do not cross her path. Corellon himself considered her as the strongest Archfey. No competition for you Ainz. She is above your paygrade.
— This is all before we will take into account his divine class gears and spells that further buffs him to be a Lesser Deity with ease.
This is all I know and can tell about his status in the DnD in terms of defenses. His offensive capabilities are upto debate.
He is definitely a Tardigrade in the FR. Small, yet resident to most damage. An overmage that is extremely hard to lock at one place or finish him for sure.
And we are still not counting his Super Tier spells. He has no Epic boons and Feats to bolster his powers. Eventually, he will get them too. There is no need to hurry for it.
— This is all I can tell about his position in the FR. You can certainly bring points of your choice, but it matters on the storyline. As I said, he is not the strongest guy, but he is certainly not the weakest either.
The thing is : I can't post stories for few months. I wrote this story on my mobile phone and it causes several grammatical mistakes for sure. Though I hope this waiting end as fast as the time goes.
Jay Bajrang Bali~!