#keldyn

FIrst, I must ask: the place you heard his name was Deon, was it a video by Spector Creative?

If so, Spector Creative is the handle for Scott Neithlich who did work for Mattel for many years and was, in fact, the head writer for the Classics-Line comics. But, he has developed a bit of a reputation for asserting his own headcanons as actual canon. If maintaining the division between canon and headcanon is something that's important to your fandom experience, I would recommend finding a secondary source to confirm his information.

Which is exactly what you're doing here.

As far as I know, the name Deon was created by Scott Neithlich and was solely used by Scott and only Scott. All other literature on Skeleteen either lists his name as "Malkyn" or leaves him unnamed beyond just "Skeleteen".

There is also an UNOFFICIAL Masters of the Universe guidebook made by the die-hard fan gbok(sp?) that lists Skeleteen's real name as "Keldyn". But I personally don't like that name as its just Keldor's name and Lyn's name spliced together and we don't see any other characters on Eternia who're named after their parents (except for Teela, but that's a very special case).

Between all three names given for Skeleteen, I like Malkyn the best. Not just because its canon. I like the way its spelled, it looks aesthetically pleasing on the page, and I like the way it sounds. It's thenically ambiguous enough that it fits in really well with some of my headcanons about Evil-Lyn and Zalesia (spoiler: my headcanon is that Zalesia belonged to the Eternia equivalent of my own culture IRL).

But pretending we didn't know the name "Malkyn" existed for him and our only options were "Deon" and "Keldyn", I prefer Deon.

Anyway, sorry to bog down the answer to your question with my useless opinions.

tl;dr

Scott Neithlich did used to work for Mattel and, in fact, was the head writer for the Classics Line and their companion mini-comics. He was also the creator of the character Mighty Spector.

However, he did not create the character Skeleteen. Skeleteen was created in the late 80s/early 90s for the "Dare, Son of He-Man" cartoon that, sadly, was never made.

But, since Skeleteen's real name was never used in his only canon appearance (the Classics comics) then you/fans can use any name you want to use for him. Deon is just as valid as Malkyn, which is just as valid as Keldyn. You can also make up your own name for him if none of those resonate with you.

The great thing about Word of God versus Canon is that canon is what gets formally produced and distributed and viewed by the audience. Word of God is just what the creators have to say about the characters or world. Some of it can be concepts that were scrapped, some of it could be details that just weren't included because of time constraints. Word of God is interesting trivia, but it is not canon. Its up to each individual fan if they want to incorporate Word of God into their transformative works.

Never forget what Rob David, Mattel's head produce said:

Deon?