The Year of the Five Emperors is strictly speaking AD 193.
Like many of my Revelation 13 theory, you should read what I wrote here first.
I started this train of thought focused on Pescennius Niger.
Let’s start by repurposing an aspect of my Vespasian model, where I started the count of the 7 Kings identified with the 7 heads with the first Emperor during the lifetime of who would wind up being the 8th King. Pescennius Niger was boring in AD 135 during the reign of Hadrian, coincidentally the same Emperor during whose reign I believe Revelation was written. Let’s say his adopted son Verus is briefly counted as the second king by Revelation even though most historians don’t consider him to have reigned, 3rd would be Antoninus Pius, 4th would be Lucius Verus, 5th would be Marcus Aurelius, 6th would be Commodus and 7th would be the short lived Pertinax (Didius Julianus was never recognized in the east just like Vitellius during the years of the 4 Emperors). And so Niger became arguably the 8th Emperor of his lifetime, there were seven Heads he had served under before reigning himself.
Why Commodus is referred to as the Present King in Revelation 17 could be because of the AD 190 relevance I’m about to discuss.
And you can also argue by connecting Matthew 27:25 to Exodus 20:5 & 34:7, Numbers 14:18, Deuteronomy 5:9 and the common theory that a generation is 40 years Biblically to argue that the final Judgment on Ancient Judea would be 160 years after the Crucifixion. An AD 30 Crucifixion then leads us to AD 190 the same year Pescennius Niger was made governor of Syria according to some sources. I don’t like to bring up Matthew 27:25 because of how it’s weaponized by Antisemites, but in this context I”m making the point that any judgment ordained for Jews for that was fully fulfilled before the end of the 2nd Century and therefore cannot be used against Jews today.
An administration of Syria that starts in 190 or 191 and ends in 194 can fit 42 months.
According to the Wikipedia page for Syria Palestinia we don’t know who that province’s governor was between 186 and 198 so given the ancient precedent for this region being under the authority of the Governor of Syria, Niger could have basically been running things in Judea before he was even an Emperor.
The popular history of Revolts of the populations of followers of Abrahamic religions against Roman rule usually jumps from the Bar Kochba Revolt to the time of Constantius Gallus in the fourth century. But there are references to some sort of strife involving the Jews and Samaritan of Syria Palestina during the time of Pescennius Niger usually connected to the Year of the Five Emperors with a popular view being that the Samaritans were pro Niger and the Jews were pro Severus which does fit Serverus enacting somewhat pro Jewish policies later like allowing them to visit the Temple Mount once a year on the Ninth of Av (that wasn’t a thing before him).
The Tenth Legion station at Laijun/Megiddo is believed to have factored into that conflict.
The wikipedia page for AD 190 says Egypt suffered an Economic Collapse then which you could link to the Black Horse.
The King of East could be the support Niger got from Mesopotamia kingdoms like Hatra.
There was a great fire in Rome in AD 192 in which libraries were destroyed.
Aselluis Aemilanus who was proconsul of Asia could be a False Prophet candidate. Niger is known to have had sons but we don’t know their names.
Niger not being recorded to have received any Pharaonic worship in Egypt is an issue for this theory however, based on the subtext I see in some aspects of Revelation 13 I do think The Beast is being framed as a Pharoah. He was recognized as Emperor in Egypt, so some worship could have happened that we simply don’t have surviving records of.
Making Septimius Severus the Seventh King would have poetry to it given that Septimius literally means Seventh, though that has the problem of his reign not being short. Some do read Revelation 17 as making most sense if the Eight and Seventh are the same somehow, maybe in Severus’s case that he’s the Seventh king at first and the Eight once he’s disposed of all the rivals. Severus was born during the reign of Antonius Pius, meaning the 2nd and 3rd emperors of his life were Verus and Aurelius, 4th was Commodus, 5th was Pertinax and 6th was Didius Julianus making himself the Seventh. Severus did have two sons who were made co-emperors before he died, the senior was Caracala.
Going back to the plausible importance of 190, it was that year Septimius Severus was first appointed Consul.
Mesopotamian vassals of Parthia who had supported Niger fought a war with Septimius Severus in 195 and then Severus fought a War with Parthia in 196-197, during which Severus conquered Babylon. But he also at this time had to briefly conquer Rome itself to dispose of Clodius Albinus.
Septimius Severus had two sons who had been alive since March of 189 but each less then 10 years till April 198, Caracala and Geta, both were made official Co-Emperors On January 28th 198, though Caracalla had been Caesar since 195 or 196. So that can be relevant to my theory about The Image of The Beast.
Despite Persecution of Christians happening under Septimius Severus reign Tertullian describes the Emperor himself as being well disposed towards Christians, he’s also remembered as being one of the more benevolent Emperors towards The Jews. So that could factor how my Baptism of The Beast premise fits Severus.
A candidate for the Beast from the Earth in this Severus view could be his father in law Julius Bassianus the High Priest of Elagabal at Emesa (modern Homs Syria) and a descendant of the Seleucids.
But another could be Praetorian Prefect Gaius Fulvius Plautianus.