When you work your way through the “Twilight Cathedral”, you will fight Tiamat. This is not a very hard fight. When you see a chance throw a bomb and then take out your crossblade, lock onto the fire that is all around, and move the fire onto the bomb on Tiamat. It will explode and she will fall to the ground. Run in and start attacking. When she gets up she will do a few strafing runs, so dodge out of the way until she stands still, then repeat the attack. When you hurt her enough, you will be able to fight her on the ground. All I did was rush in, attack a few times, and then rush out. When she jumps high in the air, run away because she is going to do a ground smash. She may also rush you and you will get a quick time event when she hits you. Press
and if you win the quick time event, you stun her.