: There are a series of terminals throughout Halo 5 that chronicle the journey
: of an 'undesignated Forerunner Builder'. He is searching for someone or
: something called 'Bastion', and unwittingly finds himself on Genesis
: during the events of the game. The final terminal details that the domain
: is 'repairing' (either him or itself, or perhaps Bastion?), whilst the
: ancilla and the Warden are distracted... and then he finds Bastion,
: 'alive'.

: So, who or what is Bastion? I'm guessing it's a place, as the way he talks
: makes it sounds like a last defence... a refuge of some kind. These
: terminals prove that there are other Forerunners alive out there, so
: perhaps he is searching for their final enclave. It's worth noting that, I
: believe, the terminals span the hundred thousand years since the rings'
: activation, as he talks about both the Domain and the Organon being
: destroyed after the firing of the Halo array.

Definitely something to watch for.
I've been toying with ideas for a fanfic that revolves around fringe Forerunner life (least impact to existing canon :).

But I would say, if they're introducing something new in a covert element of the gameplay, then they have a reason, and they're likely planning to expand on it in the near future; either in fiction or a spinoff or new game arc..something.

Then again, Sadie's Story was just Sadie's Story in ODST. So, *shrug*