Here is the full list of all 12 Mythic Ocean (EU) trophies - there are 11 gold and 1 platinum.
Collect all previous trophies.
Finish 1 Fable.
Find out what's behind that metal gate in the Kelp Forest.
Witness Lord Poison's inaugural concert.
Ride 5 whirlpools in the Kelp Forest.
Knock a beaker or tank out through the bottom of Alethea's lab.
Spend 30 seconds in Lutra's pod.
Meet 25 NPCs.
Collect 9 Pages.
Meet 40 NPCs.
Collect 18 Pages.
Witness the creation of a new world.