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If you plan on completing the whole campaign there is even a faster way to get this achievement as you will have no need to invest extra time into boosting the multiplayer games. Along the way you will earn at least 8 titles.
You will earn 5 titles for completing the campaign:
Recruit - Complete the Tutorial
Chief - Complete the Freemen campaign part of the game
Admiral - Complete the Pirate campaign part of the game
Baron - Complete the Cartel campaign part of the game
Emperor - Complete the Empire campaign part of the game
You will also earn 3 titles for unlocking each Multiplayer Map:
Traveler - Unlock all 2 Player Maps
Explorer - Unlock all 3 Player Maps
Navigator - Unlock all 4 Player Maps
Now for your 9th and final title you could always go for one of the 'lesser' multiplayer titles, but what i did was the following: Everytime i saw i was losing one of the campaign battles, i just pressed start, clicked on "Exit Game" and went back to the Main Menu. I mainly did it because i saw no point in spending more time on an already lost battle, but when i finished the whole campaign, the game also awarded me with the "Crusader" title. (I did NOT do it in one sitting and i did NOT replay any stages after i won them.)
Crusader - Complete all Empire Campaign Levels in successive order without losing
If that infact does work for everybody (which i am not 100 percent sure of, but i hope so) it will net you 9 titles altogether and that is what you need for the achievement.