Persona 3 Portable

This achievement can be unlocked after beating the Hierophant and Lovers bosses on the Full Moon event for July (7/7 at midnight). Unlike the last Full Moon bosses (Emperor and Empress) you'll have to beat each one separately, while picking completely correct answers for storyline dialogue answers in between the boss battles as well as breaking a pair of mirrors situated on different floors in the hotel complex before you can face the second boss (Lovers), who'll happen to be in the same room you'll need to find in order to fight the first (Hierophant). Unlike Emperor and Empress, this pair doesn't hold any elemental weakness affinities, but beating them shouldn't be too difficult, especially if you've done big grinding sprees for money and XP with your party in Tartarus beforehand. And the only things you need to avoid using concerning attacks is Electric types for Hierophant only (he'll repel), as well as Hama and Mudo (Nullfy for both) on that and Lovers, though odds are you still won't have a Persona with attacks of the latter two, but still vital info worth mentioning. First, the preparations...

You'll start from the surveillance room situated inside the dormitory that doubles as S.E.E.S. HQ, giving you the option of who to pick for your party, double-check on everything for equipment, and save your game before proceeding to the love hotel. Since Hierophant can repel an elemental attack that one of your party members has, you may need to sit Akihiko out for this one, although you can still employ him for the basis of using his special physical attacks like Sonic Punch even though they come at the expense of HP. Two moves from Hierophant you should be wary of are Prophecy of Ruins (Can inflict fear in your party and prevent you from making command actions, can be removed with Me Patra Gems) and Zionga (Electric attack which Yukari is weak to, but you'll need her for party healing purposes since she should have Media). If you happen to have a stock of Magic Mirrors (which repels one magic attack for each party member) it wouldn't be a bad idea to use them, either for Hierophant and/or Lovers (who'll have a fire-type all-foe attack called Maragilao, which exploits Mitsuru's weakness). Lovers will also helm Marin Karin, which will prevent you from getting any command actions to afflicted party members, Charmdi spells and Dis-Charm items should be first priority if and when they happen. Now, the getting there...

You'll start from the first floor of the building, and you'll need to find the room on the third floor in order to fight Hierophant. There'll be shadow enemies on all floors, but you can get around them without triggering their attention to come at you and initiate unwanted battles. Look for any sets of stairs sitting at the sidewalls that lead in the upward direction. For the first floor, the stairs are straight ahead from where you start. On the second floor, go to the southwest corner where the set of stairs are indicated on the bottom-left screen minimap and you'll get the stairs up to third floor. From there, go to the southeast corner indicated on the minimap and you'll find a set of doors where upon approach you'll get the bottom right text indicating "Hierophant's Chamber" Enter the doors to trigger the first boss fight. Strategy-wise, start with a party-buff or boss-debuff spell, then Magic Mirror (if you have any) and then use your best attacks that can damage Hierophant.

Once it is beaten, interact the door where you had entered the room from at the right end of the screen (it'll be locked). Then interact with the mirror that's in the bottom-left corner of the room minimap (top-right portion of the screen). Here, you'll have to answer four dialogue choices coming from a Voice in Your Head, that will try to convince you to agree with what it's telling you, and you simply pick the response that best summarizes you reject the notion. The correct responses should go as:

What was I...? (1st)
That's not true... (2nd)
I can't give in... (1st)
Not now... (3rd)

Afterwards, you'll regain consciousness, and more storyline dialogue choices will pop-up, choose them any way you see fit for they won't impact the fate of your progression. Now, you'll need to break a pair of mirrors before you can go back to the Hierophant's Chamber to fight Lovers. Start with the second floor (you'll get more storyline dialogue choices upon entering the second floor, choose any) then go back to the third floor, and head to the northeast portion of the floor until approaching the set of room doors where the accompanying bottom-right screen text reads Room 304. Enter it, find the mirror, and break it. Now go back to the second floor, and go to the southeast portion of it to find the room doors for Room 205. Repeat the same process as the previous room, and then go back to the Hierophant's Chamber to fight Lovers. Use the same strategy you used for Hierophant until you defeat her. The achievement will pop on screen once you get past the battle results screen and the storyline aftermath ensues.