Oceangreen Theme Progression

To fix the timeline in Oceangreen you need to defend the Oceangreen Village from the threat of the Bertoxians. To do so you first need to gain noteriety in the Keep, start with Sergeant Bronal Cadran found out at the guard tower near the path leading to the Karanas:

Man the Defenses
No Cure for Death

Once you have aided the sergeant Captain Hiran Tillin will speak with you. You can find him in the Keep proper, up two ramps and to the left. He'll send you to get familliar with the village:

Familiarity is Key

You then need to gather a group and knock out two group missions:

Stop the Contamination
A Dread Challenger

Next on the list is the liberation of Blackburrow. You will need to complete the group task Beat the Blackburrow Boss. To request this mission you will need to do a few other tasks, but if you have someone else get it, this is all you need. After defeating this Raxtor says he can attempt to reclaim Blackburrow which restores the timeline and completes the Oceangreen theme's progression.