Harald Blood-Axe
Sigurd worm-in-eye
Leif the Happy
Karl the Fat
Æthelræd the Clueless
Henrik Birdcatcher
There was some guy the Vikings in England called “child-lover” because he didn’t like to put children’s head on a pike. Sentimental bastard huh?
Vlad the Impaler.
Does exactly what it says on the tin.
Ivan the Terrible. And he didn’t get the name because he was a terrible cook either.
I submit Thorfinn Hausakluif (SkullSplitter), the Seventh Viking Earl of Orkney
Also the namesake for an appropriately named beverage.
King John sort of got the short end of the stick with “Bad King John” and “King John Lackland” 
I wish I had seen this thread before I named my WoW character. Great names. 
You have all missed the obvious ones: Vlad the Impaler & Long Dong Silver.
See post #42
I recall a character in The Scarlet Letter described as “redding up,” meaning that he took council, acted upon wisdom, etc. But if I google that phrase, all I get is the modern sense “to clean up.” Huh!
No one mentioned Charles the Hammer? That name is cool enough to make up for all the fats, shorts, and balds the french dealt out. He was also Charlemagnes grandpop
I knew a guy who’se last name was Matamoros - Moor killer. Coolest last name ever.
Just to prove that not only the French were fat, there’s a famous king of Leon who was named Sancho the Fat. The King of Navarre during the beginning of the Hundred Years War was nicknamed “Charles the Bad”, and his sometime ally/sometime enemy, the king of France was “Jean the Good”. The French king’s ally at this time was the King of Bohemia, “John the Blind”, who was.
An earlier king of Bohemia was “Boleslav the Cruel”, who was, and his son, who was probably crueler, manged to get the nickname “Boleslav the Pious”. Then of course, there was the later King of Bohemia, Frederick the V, who was given the throne by a bunch of Protestant nobles at the end of 1619, and then overthrown only two months later by the Holy Roman Emperor. This got him the nickname “The Winter King”.
You missed my post #16. You also missed “John Softsword”, which, as I note above, probably does NOT refer to his lack of military prowess!
Why? What do they call him?
Syviatopolk the Accursed, Grand Duke of Kiev. Wonder what he was cursed with? Bad breath? Acne? Gouty legs? Whatever it was, I’ll bet it was unpleasant.
As far as badass nicknames go, there’s Contantine Monomachos, which means “He who fights his own battles”. Sounds even better on his grandson, Vladimir Monomakh. Vladimir Monomakh totally sounds like a dude who could kick some ass nine ways to Sunday.
Hammer of the Scots (Edward I)
Yes indeed. Especially that early episode where he was deciding on a badass nickname for himself:
“I SHALL CALL MYSELF… dramatic pause THE BLACK… ’nother dramatic pause vegetable”.
Then there was Carlos II el Hechizado – Charles II the Hexed, the last Hapsburg king of Spain. The prince suffered from developmental problems both physical and mental, major sexual dysfunction (terrible when you’re supposed to sire heirs) and on top of it all at the end he started going mad. Folks figured he must have been bewitched.
Yeah. I didn’t realize Bush killed Uday and Qusay and captured Saddam. 
If he’d done that, somebody probably would’ve thought up a good nickname for him.
Naw, just really really inbred.
Btw, I dug up the reasoning behind the name of Svyatopolk the Accursed. Seems he got stuck with the role of official villain after murdering (or did he?) three of his brothers. Medieval Kievan history is notoriously twisted, so perhaps we’ll never know the truth. In any case he had eleven brothers, it’s not like anyone would miss two or three.