Axilus Prime

Story filler*

Wasn't that either. An introduction to Osiris and Jul 'Mdama's death, an introduction to the members of Blue who aren't Chief and the reason for their going AWOL, the hunt beginning, Warden's introduction, Chief beating Locke and leaving, Blue Team first starting to suspect something's up with Cortana along with bits of her plan being revealed, Osiris meeting up with the Arbiter, the alliance getting what they need to follow Blue Team, the final battle with the Covenan...

...t (save for the stragglers still on Genesis), Osiris searching for Blue Team on Genesis and finding them, Blue Team getting transported away and making their way to Cortana as the Gateway finishes up on giving her a physical body, ending in their imprisonment, and Osiris freeing them while everyone escapes to prepare a resistance in Halo 6. Absolutely none of that was pointless filler meandering. It was all absolutely necessary and beneficial to the story as a whole