Part 3 (final)
I would keep all three names.
One of the things which annoyed me in Battle for Mewni is that Toffee was a prince and general who got Comet killed but nobody knew about him in Seasons 1 & 2.
So, if we mix all three characters into one and use two of the names as fake ones, it all make sense:>Seth, Prince of Septarsis, King of the Dark Monster Nations and consort to the Queen of Mewni.
Real name and titles during Solaria's/Eclipsa's reigns. Guess he dissapears after Shastakan's murder to search for his child (never finds her) and doesn't return until Comet's reign, as he hears she is interested in a peace treaty.>Globgor, Archiduke Batwin's general and Plucker of Limbs.
Fake name he uses to infiltrate Comet's peace treaty. He gets the title due to the brutality used while murdering Comet and her court members.
Only Moon knows Globgor and Seth are the same person after a conversation they share.>Toffee. Ludo's personal assistant.
Nickname Eclipsa gave him and which he uses to gain Ludo's trust. Moon just links the dots after Season 1 finale.