Since "Protector" is actually a title for completing all the missions in a campaign *with* bonus objectives, the wiki article you read might be referring to completing Faction-specific missions such as The Eternal Grove and Gyala Hatchery. These missions represent a (temporary) split in the storyline wherein you have to choose whether you wish to side with the
Kurzicks or the
Luxons before continuing on. You can go back and finish the missions on the other side later, but it's best to play through to the end of the campaign on one or the other first.
The problem with the split is that you can accumulate faction from both the Kurzicks and Luxons at the same time (press "H" to view how much you have)...but when you go to spend it, you loose an equal amount from the other faction. Most ppl run one side and then switch to the other later to avoid too much faction loss.
Apologies for the sloppy linkage to wiki pages...heading out to run errands in a min >.<