So I was thinking lately and it struck me that if there is a warthog, there will have to be some marines to man the gun and most probably a human ship to provide all this armament for the chief. And it hit me that the perfect candidate would be the Spirit of Fire, as last we saw her she was flying through space with no FTL drive and a cryo-ed crew. Serena (the AI) at the end of the credits is heard saying to wake the captain and that something has happened so that isnt the end of it for sure, also achievements say ready for sequel and while I would prefer a halo wars 2 with enhanced features and fixed bugs, maybe thats what they meant seeing as there is no chatter of a second halo wars and 343 admits to not even bothering with one at the moment. Just throwing the idea out there.
because marines
Frankie confirmed the the Spirit of Fire wont make an appearance at Halo Fest.
> Frankie confirmed the the Spirit of Fire wont make an appearance at Halo Fest.
Damn. Still, it wouldve worked
Maybe this means we’ll finally be able to use the turret while in the driver’s seat. Or maybe Cortana will take control of it for us. Or marines are on the shield world.
The most likely scenario is Arbiter teleporting onto the turret like he does on the last level of Halo 3. 
The concept art for Halo 4 shows some UNSC ships going into the shield world including the UNSC Infinity which has spartan IV’s on it so thats where the marines and warthogs etc come from. Still it would be cool if the Spirit of Fire were to make an appearance but then again all their tech would be almost 30 years old and i don’t know about you but i want the chief to have the most upto date high-tech weapons at his disposal.
If you guys read some of the more recent books like halo glasslands and halo primordium. they do hint that we will see The UNSC in the halo 4 campaign.
Also The chief is floating around space in the -Yoink- end of Forward unto Dawn with a few vehicles.
May be chief runs into some Forerunners that join him in his destiny.