Trilobite Keys:
1... underground lake before World Saviors Fight
2... won RANDOMLY from zombies infesting Canonia
3... In Social Fox's Tomb, go back in after killing Moric
4... Given to you In the Goznor Inn by the Bandit you spared in the exam
for 1st you need your map, it's not in a conventional chest, and for 2nd you might have to leave the area and return if you've killed all the zombies and they haven't dropped it yet.
the final bosses are simple, I'd say ignition is the toughest. Block and shatter bolt are key, and cripple is incredibly effective on omen, just wait till he buffs himself with his signature buff, cripple him, and then shatter bolt him.
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