Persona 5 Royal

This achievement ties to the boss of the Cruise Ship palace...which is the cognitive form of the main antagonist for the game, Masayoshi Shido. And given this title, your battle with the Prime Minister hopeful will be sheer in scale from a standpoint of HP banks and impressive offensive firepower to go with an array of buff and debuff skills, as well as having to beat him in five different forms, the last of which you'll need to defeat with ONLY Joker available. With a task this tall, it's a lot to divulge, but if you've learned
and mastered everything so far from the perspectives of combat, Persona raising and fusing, and Confidant ranks, you can crush Shido and his dreams easier than you'd think!

Starting from preparation, you can go with pretty much anyone as long as they at least have one magic and one Physical attack skill in their moveset, both with at least the Heavy damage scale. If they have an all-ally stat buff spell like Matarukaja, that's even better (and pretty much worth prioritizing for deployment.) And more importantly have one party member that has healing skills, especially Mediarahan, in your crew here, which should be Makoto. For what Persona(s) you should have, have those that can nullify/resist physical attacks, or at the very least those with as few weakness affinities as possible if any. Those special accessories you've gotten as a result from acquiring the Will Seeds in previous Palaces and getting them converted by Jose in Mementos will come in handy too. At the very least you should equip the Ring of Lust on Joker. It gives you the Champion's Cup skill in your moveset, at a cost of just 10 SP it will heal you a medium amount of HP and also buff your Attack stat for three turns. This will serve you very well when you fight Shido's final form: When you get his health down to 1/4 of his heart gauge, he will forcibly isolate your party members from you, and you'll have to finish him off solo. With that said, let's move to the battle.

For his first form, Shido will mount on a lion-like creature, called the Beast of Human Sacrifice. This creature will morph two other times as you knock down their health, their resistances changing along with it. For the initial form, it'll repel physical and gun-type attack skills, but holds no resistance to any elemental attack spells, so use the latter here. Beware though that they also have Makarakarn which can repel a magic attack for one turn and Wage War which can inflict Rage on all party members and anyone afflicted will automatically physically attack and hurt themselves, so use these situations to just heal, remove ailments, and buff up your party. Next up the Beast will grow wings and take flight, becoming the Wings of Human Sacrifice. This time it's resistant to all magic attacks, but now can take normal scale physical and gun-type attack damage. This form's trump card is an array of heavy damage elemental spells targeting a single foe, fortunately there's no defensive skills, so emphasize putting forth your strongest attacks and again keep your stat buffs active. The third form has the creature transform to a pyramid-like structure, called the Tomb of Human Sacrifice. No resistances or weaknesses here for physical and magical attacks, while holding Almighty-type attacks targeting your party. Again, offense is your best defense with deploying your strongest attacks. After you empty its HP heart, you'll bring down the beast creature, and Shido will dismount and shred away his political dictator-inspired outfit to show his muscularly ripped self, and it's now getting to be serious business.

For this form of Shido, now in Samael form, he will have a pair of Physical attacks, one targeting one foe and the other targeting all foes at Heavy and Medium scale damages respectively. But what you should really look out for is the Heat Riser skill, which bolsters Attack/Defense/Agility for three turns, so if you have a Persona or party member that has Dekaja, use that to remove Shido's buffs. As a suggestion, try to prioritize physical attacks as much as possible, by this juncture your collective SP for your party is starting to run low. You should have a Soma or two from your Palace exploits in your inventory for when you need it, recovering all SP for your party. When you drain the HP heart for this form of Shido, you have an impression this battle is over, but sure enough, Shido has one more trick up his sleeve, breaking off the shackles and showing off his True Samael form.

For this final round, Shido will have attacks of every element in his moveset, along with an Almighty all foe-targeting attack called Tyrant's Wave. Continue to fight as you've done since the first Samael form until you get the percentage of his HP heart under 25% or so. There Shido will create a barrier to force out all your teammates away, leaving the battle between only Joker and Shido. This is where the Champion's Cup skill comes in handy, especially as Shido will only use one move per turn now. Alternate every turn between using the skill and a physical or magical skill. Follow this pattern until you defeat True Samael Shido, and now enjoy the aftermath of cutscenes to follow as you savor your revenge!

Like all the other Palace related achievements before this one, the achievement will pop when you advance to the deadline of when you need to have your Palace treasure raid completed, which is 12/18 here, or rather you need to send the calling card no later than 12/16. When you get to the cutscenes highlighting the elections for Prime Minister, the achievement should pop.