Help with Last Day Dawns

Has anyone completed this quest? It's pretty difficult because you only have 4 people and on top of that you need to keep the king alive and kill those titans. I think keeping those allies alive might help but most of my grps didn't bother to do that.

When I completed this quest the King ended up dieing. But after we cleared all of the titans the quest log told us to talk to the king. Then we just went back to town and then back out again to talk to the king. We just grinded through it and it didn't matter how many times we died.