I'm impressed that people here can even name Marathon. Weren't they all released only on the Mac in the mid/late '90s?
I loved the atmosphere in Marathon! But there's near zero chance that Bungie is working on such an unknown franchise. Same with Myth. I never got into the Myth games because the difficulty level was insane.
Normally there would be a decent chance to know what Bungie are up to, but nowadays there really aren't many interesting new games revealed at E3.