So I've been attempting Titan the last few days, and have noticed Duty Finder is not exactly the ideal method for this battle.
The two things that make Duty Finder a pain:
1. Forces you to have 2 tanks (This fight only requires one)
2. Everyone has to know the patterns of Titan's moves like the back of their hand.
Below is a video link of the fight. It will tell you far more than I can in words.
Titan Hard - Win Video - http://www.youtube.com/watch?v=to_9IjxTF54
I advise anyone attempting this fight to watch this video from start to finish a few times as I did until you see the pattern for yourself, but to help a bit I'll post the order below.
To beat Titan's Heart-
Once it has appeared, It's important for players to start damaging it immediately as this is timed. Shaving off a good chunk of its HP right as it appears will help you in those last few seconds. During this time frame, he will use a move which creates a rock Gaul, targeting a random individual and locking them within a barricade. Only the FIRST gaul should be destroyed, and second ignored completely, regardless of the person inside. There just isn't enough time to take out both. Save your DMG boosting abilities for this!. If there is a Limit Break available, try to save it for the end of the fight, if possible during his stomping ability, to insure you aren't knocked off or damaged due to animation lag.
The music will really turn up here, and give you the sense of urgency, although really the only difference now is that Titan will change his pattern slightly and add an extra 2 rock formations to the mix. Other than that its the same and it repeats itself so nothing new to learn once you have it down the first time.
So for the sake of me not knowing exactly what the name of the move is, I'll name it "Tank Attack". (Titan reaches down and grabs chunks of the ground and hurtles them in a fan (usually towards tank). This is the beginning of each of the two patterns he will use at this point.
PATTERN 1: (Tank Attack) -> (Ground Stomp) -> (eruptions) -> (Rock Bombs) > (Line/Knockback move.)
Titan will return to tank after Pattern #1 and begin Pattern #2
PATTERN 2: (Tank Attack) -> (Eruptions) -> (Gaul Single target Lock) -> (Line/Knockback move)
If you watch the video you'll notice this as well. He will repeat PATTERN 1 -> PATTERN 2 -> PATTERN 1, so on over and over, and the only difference will be on his (Rock Bombs) ability. These will change between 3 different versions.
The first group of Rock Bombs he will spawn will be in a different arrangement from what you've seen so far. He will slam his fist into the ground and rows of rocks will spawn in a 3x3 grid across the entire map. The last group of 3 rocks that land will be the last to detonate, so those will be the first group you run to. During this time Titan will turn and try to use that knockback move while you avoid the bombs. Once the middle group has detonated, quickly move across to avoid death or low HP.
Titan will spawn rocks in a circular fashion with the last rock to detonate in the very middle- exactly like his move earlier in the fight.
The third time around he will spawn a group of 4 rocks in a diamond shape @ the center of arena, and single rocks at each corner of the arena. For these you will be running to the side the tank is on, upper left corner. He will use his knockback ability at the end of each of these, followed by the "Tank Attack" to start the cycle once more.
You will repeat this process until he is dead. Good luck!