javert's priority is going to be to investigate the labs and see if there's any further research on how to stun or weaken the world eaters or green-eyed spirits. he'll especially be looking for some sort of recipe to create the potion they used in the world eater fight. if there are any directions on how to construct a bomb or weapon, he'll be interested in that, too.

he'll more than likely help cao pi get the underwater lab unflooded, since there should be some good information there.

he will have his two pistols with him and his sword, along with the notebook he found during the key retrieval explore.