I couldn't help noticing that Hammer Shield's cutie mark is the Marathon logo. I'd love to hear the story behind that one. ouo
In my design of Hammer Shield (an OC in my incredibly slowly-written fic), I needed to come up with a decent cutie mark. As the fic is about a pony grifball team, it made sense to find a Halo-related mark. I decided on the Marathon symbol since I could argue that the outer circle is representative of a shield and the inner circle (and vertical line) are a head-on view of a hammer. As for the actual image (used in General Zoi’s Pony Creator), I took the symbol from a collection made available on HBO ages ago.
When writing, I always tend to be bad at coming up with names. In ponysona terms, that translates to cutie marks (pony names are easy, comparatively, since they tend to be phrases or compound nouns). Incidentally, I never quite figured out the marks for the other characters in the fic though they all have rather detailed backstories and distinct personalities.