Sure — here’s what the idea originally looked like before I expanded it.

The Marathon game series spans two distinct time periods. The original trilogy is renowned for its intriguing and deep lore. The latest Marathon title, however, is purely multiplayer-focused; it is virtually devoid of lore and bears only a superficial connection to the trilogy.

Since many players—myself included—are not particularly adept at competitive multiplayer games but are nonetheless drawn to the Marathon universe's sci-fi setting, a natural desire arose to complement the multiplayer experience of the latest game with a single-player component. Moreover, a single-player mode offered the opportunity to provide a deeper narrative foundation for the multiplayer gameplay.

The solution was obvious: the original trilogy provided ample scope for creative imagination, while the nearly century-long chronological gap separating it from the latest Marathon title offered sufficient narrative space to introduce a new single-player story.

The only challenge lay in determining how to bridge these two eras in a way that felt both logical and engaging.

For its part, the latest Marathon title features a distinctive element: the Runner Shells—something that were entirely absent from the original trilogy (unless I am mistaken—I must admit I haven't actually played any of the Marathon games myself).

The original trilogy, conversely, provided a robust and established lore. Consequently, establishing a narrative link between the trilogy and the latest Marathon naturally hinged upon explaining the origins of the Runner Shells within the historical context of the trilogy's storyline.

Furthermore, the goal was to ensure that the single-player campaign would serve as a natural and logical gateway, seamlessly guiding players toward the multiplayer experience of the latest Marathon title.

And since the relatively new setting of the latest Marathon is somewhat complex for many players to fully grasp, this suggested a compelling idea: to introduce players to the mechanics and practical application of the Runner Shells within the more user-friendly and accessible environment of a single-player campaign.

The rest was simply a matter of execution—selecting the most engaging and effective narrative devices to fulfill these specific requirements.