Who is the Gaiseric of Berserk based on?

I'm going to do something unusual and engage in some theorizing about a fictional story I haven't actually watched or read anything of yet.  I'm planning to watch the late 90s Berserk Anime someday, but I need to get myself in the right mindset for something that dark.  But when you've been in the Anime community for a few years like I have now it's difficult to not hear a lot about Berserk.  Berserk comes up in videos I watch about other Anime, which puts more specifically Berserk based videos on my recommended videos feed, which leads to me deciding to click on ones with interesting titles.

Berserk is a Medieval European fantasy story, but it seems to be drawing more on Continental European history as opposed to the usual British Isles focus of Tolkien/Lewis, Game of Thrones and Final Fantasy Tactics.  Gaiseric is a figure in the lore of Berserk who most fans seem to think is partly based on a real historical figure, but they disagree on who with the common theories being Julius Caesar and Charlemagne.

I was drawn into this discussion by randomly clicking on this video about The World of Berserk, it argues for a theory that Gaiseric was analogous to Charlemagne and Midland is Middle Fancia from the division of Charlemegnes's Empire that Extra Credits made an interesting video on.  Which would probably make his capital either Aachen or Pavia.  But there are other theories that Midland is more just plain France or Germany.  That video has a lot of interesting criticisms in it's comments section, like how Kushan being a Muslim empire doesn't make that much sense.

But there is something I'm sure I'm not the first to notice, but it doesn't seem to be a popular theory.  And that is that there is a real historical figure literally named exactly Gaiseric, a Fifth Century King of the Vandals.

The Vandal Gaiseric reigned for about fifty years ending in 477 AD.  In Berserk Gaiseric is supposed to have lived about a thousand years before the present narrative, which seems to be from what I gather near the end of or following a fictional analogue of the Hundred Years War, which was about the mid 1400s aka the 15th Century.

Most maps you see of what the Vandal Kingdom looked like are based on what they had during the time of Justinian who sent Belisarius to conquer it, which was the same chunk of North Western Africa Rome used to control and some Western Mediterranean islands like Corsica and Sardinia.  But Gaiseric ruled more having conquered all of that and a decent chunk of Italy, he even sacked Rome in 455.  Still he didn't ever rule the main countries Midland seems to be based on, but maybe Bersek is an alternate history where he ruled far more then he did historically?  The origins of Gaiseric do seem to be a mystery to the people of Midland.

Pavia also seems to have never come under Gaiseric's control, but it was becoming the real capital of Italy already in Gaiseric's lifetime.  In an alternate timeline where he conquered all of the former Western Empire, it may have become one of his capitals as well.

Their Tax Policy is complicated to compare, Berserk's Gaiseric is simply said to have levied heavy Taxes, the Vandal Gaiseric taxed the Nobility but not the common people.

The biggest problem with the Julius Caesar theory is that Gaiseric was clearly not someone who made a public show of refusing to be crowned King.  But there is a secondary problem.

The Holy See in Berserk is pretty universally agreed to be based on the Catholic Church (Berserk may be like a lot of JRPGs which kinda make the God of Christianity Evil, but the Lost Chapter is of disputed canonicity).  The Holy See clearly existed already at the time of Gaiseric which hurts the Julius Caesar theory.  However Gaiseric was not on the same page religiously as the Holy See which makes him clearly not Charlemagne who was very much the Pope's man, it was the Pope who crowned him Emperor of The Romans.

Gaiseric however was an Arian, a sect of Christianity condemned as Hersey at both the First and Second Ecumenical Councils during the 4th century.  But for a time between them it was popular in the East and because of a missionary sent by the Arian Emperor Constantius II it gained a lot of converts among the then northern Barbarians which included the Vandals, Alans, Goths, Suebi, Burgundians and Lombards.  Quodvutdeus could be the basis for the Sage said to have been imprisoned by Gaiseric.  That would make the Albion of Berserk Naples, that name could come from Alboin a King of the Lombards.  A lot of what we think we know about Gaiseric in Berserk seems to come from the Holy See who have a bias against him.

Arianism was a non Trinitarian form of Christianity, it taught that God The Son, Jesus, was Divine in a sense, He certainly existed before His physical incarnation.  But defined Him as a Created Being unlike the Uncreated God The Father.  There were also Semi-Arians who refereed to this Creation as being Begotten and saw their Theology/Christology as compatible with the Nicene Creed.  Modern Christian movements often compared to Arianism include the Jehovah's Witnesses, possibly some forms of Mormonism (though the Book of Mormon is quite Trinitarian and Brigahmite Cosmic Pluralism is not quite Arian either), some Unitarians, and at least one anti-Paul Hebrew Roots website I stumbled upon once.  Some have also described the Logos Doctrine of Philo of Alexandria as being kind of proto Semi-Arian, and certain anti-Arians of the Antiochene School also saw some of Origen and Clement of Alexandria's ideas as anticipating Arianism.  Some Neo-Arians look at the Old Testament and define YHWH as The Son and The Father as El Elyon, I don't know if there was any precedent for that among the Ancient Arians however.

The Arians were not Gnostic, but the potential to compare and confuse them does exist, since both the Gnostic Ialdabaoth and the Arian view of The Son can be seen as having their roots in the Platonic idea of the Demiurge as a Creator god who is lesser then the true original God.  And many Trinitarinn Christians have had a habit of grouping everyone they didn't like together.  This possible confusion could be relevant to Berserk which might like many Gnostics be viewing the God of mainstream Christianity as Evil.  And there was a Gnostic presence in the West contrary to the usual assumptions it was just an Egyptian and later Persian problem, remember Augustine himself was a former Manichean, and Priscillianism was derivative of Manichean ideas.  Also later during the middle ages the Albigensians appeared in southern France.

Another character in Berserk known as the Skull Knight is often theorized to either be Gaiseric or someone who was a loyal Knight of Gaiseric.  The later theory suggests that Gaiseric was in a way like Griffith but made the opposite choice, and the Skull Knight was perhaps his Guts. Once I've actually watched a decent amount of Berserk I may return to this subject.