H3 - Marathon? Newer ending?

[Blarg-Blarg-Blarg!]

I beat legendary on h3 and saw the newer ending. I went on youtube to see what that mechanical planet was, and the posts were talking about the planet was the mechanical planet from marathon. I also hear that Marathon is Halo 4. I looked around, and the marathon logo and helmet are in Halo 3! Anyone care to explain if Marathon is H4, and an explanation for the logo and helmet?

I also heard that if you beat the last level on legendary with every skull on, there will be an even newer ending after the credits! Anyone care to explain? H3 is not H3 to me anymore. To me, it's just a prequel to Marathon now... I need an explanation BADLY!!! I miss knowing that H3 is Halo 3, and not Marathon -1...

[Outrage]

Read Ghost of Onyx.

The planet is Onyx.
Look it up.

[Blarg-Blarg-Blarg!]

Then explain the logo and helmet.

[GametagAeonFlux]

Read Ghost of Onyx.

The planet is Onyx.
Look it up.

I believe that's not confirmed. Plus, writers of the book were given artistic freedom, so I believe what they write may not necessarily be canonical (dunno about that, anyone else have input?).

As for the Marathon logo and helmet, they're just amusing easter eggs and such. The Marathon logo's been in since Halo 1. I believe there was some article where Alex Seropian said that MC and the main character of Marathon were the same guy, but I don't know if that comment has remained true to this day.

[Tural]

I need an explanation BADLY!!!

There is no explanation. For rampant speculation, go to the Halo 4/Halo movie thread. People are babbling without reason like crazy in there.