The Nova Corps

The Nova Corps will definitely be involved in the fight against Thanos and they already have a very good reason to be right in the thick of the battle.

That reason is the Orb – the Infinity Stone that was handed over to them for safekeeping at the end of Guardians of the Galaxy – as it is one of the items the Mad Titan will need to get his hands on in order to wield the completed Infinity Gauntlet.

It is strongly expected that, by the time Guardians of the Galaxy Vol. 2 comes around, the Nova Corps will have used the Orb to create the Nova Force – exponentially increasing their power as an organisation in the process.

Once Thanos obtains the Orb from them (which is something they won’t take lying down, for starters), they will still possess some of its power as a result – and that could be a key factor when it comes to finally taking him down for good.