Again I'd like to pose the question:Nearly all of Halo 5 is filler which renders Halo 4 filler lmao.
What actual important purpose does Osiris serve in Halo 5's narative other than being a plot device to beak Blue Team out of jail in the last mission?
They take up 12/15 of the games missions and spend 11 of those literally playing catch-up with the game's actual plot and meandering on filler world while managing to not develop a shred of character as if this was Naruto: ODST.
We get to the final mission and we're in nearly the same place as we were at the start of Halo 4:
-Chief is missing/Chief is missing with Blue Team
-Covenant is still around under Jul 'Mdama/Covenant is still around under Sali 'Nyon
-Cortana is still alive, but suffering from rampancy/Cortana is still alive, but evil
-Infinity is looking for Forerunner constructs (Halos)/Infinity is looking for Forerunner constructs (Guardians/Genesis)
The only difference is in Halo 5's time there are Prometheans running about.
It's only in the final mission that suddenly there are Guardians taking over the galaxy and there's been an actual meaningful change to the universe (which will no doubt be swept under the rug).
Blue team left their armor lock at home and need to go back and get it, we don't see them for the rest of the game
Atriox and his gang overthrow the Neo Covenant - Nu Covenant are now your allies
Cortana's PMS is over and she is back to being good, she kills off all the Guardians.
Atriox finds a new Halo ring and wants to activate it
The gravemind gets revived on the Ark and now wants to stop Atriox
The Arbiter travels to the ring to stop Atriox.
They all end up in the ring's activation room and stop it from activating
Atriox spil-spaces out when he is about to die.
This puts all the other Halo rings in stand-by mode and they have to go to the Ark now
MC is on a forerunner ship. His mission is to Finish This Fight™
Chief reaches the Domain™ HQ to retrieve Cortana
Gravemind is holding her captive while learning all of the Domain™ secrets
You 'kill' the gravemind and Save Cortana
Cortana knows where Atriox is
You go to the Ark again
One of the rings is being re-built. Pre-mature activation will blow it up and kill the remaining flood
'Exuberant' gets corrupted by the flood
In the activation room, palmer gets killed by Exuberant and you avenge her.
You and arbiter escape the exploding ring