This trophy is missable but it can be achieved on your first playthrough. I got mine with Emil level 96, Marta 101 and my 2 monsters were on their 4th tier and level 88 and 94 respectively. Lower than 90+ and you will have difficulty even on normal.
The Twilight Palace is accessed through the katz quest Treasure Hunter's Trophy in chapter 8.
In order to make the quest appear you need to have completed three earlier katz quests:
Treasure Hunter's Trophy - Chapter 5.
Treasure Hunter's Trophy Take Two - Chapter 6.
Treasure Hunter's Trophy Take Three - Chapter 7. (do this as
SOON as you get to Mizuho! Time frame
VERY short.
The quest itself is very linear. Use sorcerer's ring on the lamposts and go up long staircases to each boss.
Your first boss is a plant called Pyanopsian 100+ in level.
Kill all lackey's first. They ALL heal. Mandragora's are easiest than the blue roses. You need good weapons with a high damage output. Mystic Arts are great for this battle. Boss is real easy once cronies are dead.
Your second boss is a bat. Maimakterion. Higher hp than the last boss..
Lackey's not so bad. Just kill the carbuncle's first cause they heal. Nightstalkers not much to them, so you can go directly for the boss after the carbuncles. No special strategy here.
Third boss is like a powigle? Poseideon is a
highly aggressive bossI made sure Marta cast
REVIVE on everyone at the start of the fight. Get rid of the Sieren's quickly as they both heal. The big fish monster hits hard and fast, he should be dealt with before the boss.
Last boss is Album Atrum and very tough without a strategy.
TURN OFF all of Marta's light spells and remove any light based weapons as they HEAL this boss and make it so easy for him to do his ultimate move which can wipe out your party.
Focus on his lackey's one at a time. Do not spread out and watch your health.
When everyone else is down and Album is by himself use Unison attacks to disrupt his spellcasting often.
This whole quest will take about 2 hours to complete and then the trophy will be yours!
