If there is a space inserted in the title somewhere, that sounds like it was just a mistake or an attempt at being punny. Well, I guess the title is punny regardless, considering the character wields an ax and the game is a rip-off of Legendary Axe. If anything, I think that's why they'd change the title from The Lord of King, to make it sound more similar to Legendary Axe and possibly attract fans of that game. Well, also to avoid potential outcry from Christians, haha.

But yeah, it's obvious that the name is a reference to the character from the story of the Trojan War. He's not a terribly well-known character, not like Helen, Hector, Achilles, etc, but if you're familiar with the Iliad, the name will ring a bell. "The Lord of King" is actually a (poor) translation of Astyanax, which isn't the character's birth name (Scamandrius) but rather a nickname. That Wikipedia article above offers the translations "high king" and "overlord of the city". But I don't know if that means the Japanese developers had Astyanax in mind from the beginning, or if some Greek mythology nerd at Jaleco USA saw an opportunity and ran with it, haha.

The name isn't too hard to pronounce. Like most terms in Greek, it's just composed of a boatload of tiny syllables. Breaks up like As-ty-a-nax. You can hear a recording here: http://www.merriam-webster.com/dictionary/astyanax

Anyway, as for the game itself (the NES version at least), I always thought it didn't play that great. Just kinda sloppy. The Ninja Gaiden-style cutscenes are cool, though, even if the story is pure cheese, and the music is excellent.