Echoes of the Past - In the pillars area next to the central shiny gate, talk to the Captain in red armor to initiate a retrieval quest for two Capsules. We already nabbed them, so talk to him again for AF005 BRESHA RUINS FRAGMENT - Unio Mystica (04/08) + 100CP !
PARADOX ENDING ACQUISITION
Exit to the Historia Crux, and do Time Reversal on AF005 Bresha Ruins. Proceed past the first boss battle and advance onto Atlas, WITHOUT fiddling with the machine that makes it weaker. Kick Atlas' ass to unlock the AFXXX Archylte Steppe timeline in the Historia Crux, which is where you also end up. Enter AFXXX Archylte Steppe, and view the paradox ending to receive AFXXX ARCHYLTE STEPPE FRAGMENT - Transcript: A Giant Mistake (01/01) + 10000CP ! Upon returning to the normal Historia Crux timeline, AFXXX Archylte Steppe already has Time Reversal unlocked.
Boss Tips :
Atlas has amazing amount of 900% stagger with 80% resistance, so it's unlikely you'll manage to stagger it. The battle is not much different than weakened Atlas - it still telegraphs own attacks way ahead of time allowing you ample time to switch to triple SEN to soak up the damage. The enemy is stronger, though.
At start of battle inflict Deprotect and Deshell to increase your damage output and then slowly start driving up its CG. Don't forget to remove Curse from Atlas's 'yell' attack, and switch to SAB SAB SYN every so often so that your buffs get refreshed.
At the northeast dead end in Lamentable Rest near the monument, you can talk to Jed, a man who wants you to bring him a flower, which can be found in AF300 Bresha Ruins (but we haven't uncovered that timeline yet).
In the Excavation Site talk to Morris, the guard in front of a jail cell for a quest to retrieve a comm device. But you need to get past the locked gate in the cell, so where's the key? Go to the center of the Excavation Site and find the out-of-reach treasure sphere just above the giant's hand. Use Moogle Throw to collect the Holding Cell Key . Unlock that blasted gate, pry open a treasure sphere for 10x Vitality Chip and ascend the slope into Echoes of the Past. Before making the left turn there's a concealed treasure - reveal it and grab the Army Comm Device . Return to Morris for AF005 BRESHA RUINS FRAGMENT - Vita Lyrica (06/08) + 200CP !
Next, in the Excavation Site there's Cordelia, a girl roaming around at the southeast, south or southwest end of the map, around the fenced area with that giant hand. Talk to her to initiate a retrieval quest. The item is in a concealed cube next to the jail guard. Use R1 to reveal it and nab the Personal Notes . Bring those back to the girl for AF005 BRESHA RUINS FRAGMENT - Ars Symphonica (07/08) + 100CP !
Now all that's left is to proceed past the prison gate you unlocked into Echoes of the Past and hoof it to the crystal gate. Check both dead ends for two treasure spheres with the Butterfly Bow (weapon for Serah) and a Unicorn Horn . Now activate the crystal gate with a Wild Artefact, which unlocks the AF300 Bresha Ruins timeline.