Use in battle to awaken a new Stand power. There are 9 types in all: Tower, Wheel of Fortune, Empress, Devil, Moon, Sun, Judgment, Temperance, and a dud. The chances of getting a useless scrap are 1/5.
After defeating D'arby, you'll be presented with a choice of continuing your search or stopping by the hotel first. Returning to the hotel will skip this optional event entirely - continue gatheting information to watch it.
If you went on the manga route, you simply have to find and defeat Hol Horse within 2 minutes. If 2 minutes pass before the battle ends, the events will continue as per the story without a Game Over, but you will miss out on the substantial 3000EXP. Defeating him within the time limit will also yield +1FP to all party members except Iggy.
If you went on the submarine route, you'll have a choice of either attacking him by surprise or attempting to persuade him. Attacking him will start the battle as usual and give you +2 bad karma - you'll still get the FP. Persuading him will lower your bad karma by 2, but also lower the party's FP by 1 each (3 for Polnareff). Whether or not you persuade him has no bearing on the story, but is essential to triggering a small event that occurs while fighting Dio and one particular hidden ending.
VS Pet Shop
After reaching Cairo, leave and enter the hotel 10 times to proceed with the story. You'll get +1FP for whoever is in your party at the time. You'll watch an event with Iggy and Pet Shop, followed by a battle. Defeating him will skip to the meet-up with Kakyoin. Running will take you to a sewer, where you must avoid Pet Shop's ice projectiles while fleeing to the exit. If Pet Shop catches you, it will start another battle. Taking too much damage from the icicles or successfully reaching the exit will continue the chain of events from the original story - keep in mind that there is a chest containing an Experience Tablet near the exit, so it's worth tracking down no matter how you plan to defeat Pet Shop. Just keep moving to the right and when you hit a wall move up then left.
After the event ends, Iggy will enter serious mode and start taking orders in battle regardless of your FP with him.
To Iggy's Rescue
Requirements: Iggy's FP is 10 or more
If you reach the exit with the required amount of FP, instead of simply continuing the event as normal, the protagonist will come to Iggy's rescue and join the battle. You will get +3FP with Iggy, and he won't sustain life-threatening injuries, though it won't affect the outcome of the story or his stats in battle.
Finding the Mansion
Once the Pet Shop battle is over, Iggy will lead you to the location of Dio's mansion. You can head in immediately and proceed to Dio's Manor, or head back to Cairo and prepare. It is recommended you do this, as there are a number of things in the city only available after you return:
New shops - see the section above.
New enemies: The Evil Ripple User now appears, with an EXP yield of 3000 (the highest in the game for a normal encounter) which makes them even better for grinding than Overdrives.
The boss rush can be fought - see The Scribe Ani below.
A different ending route can be accessed, which is necessary for the Dark, Sacrifice, Unrest, and Succession endings. See Final Battle Retake below.
The Scribe Ani
Requirements: Dio's mansion has been found
In the southeastern part of town, near the hospital, there's a skull-faced man in robes who only appears after the Pet Shop event. Talking to him will start (without warning, so save before speaking to him) a boss rush against powered-up versions of the 15 Tarot Stands from the story, in a row, without the chance for recovery in-between fights. You will get no money from this battle, but you will get EXP and dropped items. Additionally, you'll get bonuses after the battle: a Phantom Blood, and sometimes a random bonus of FP, EXP, stat boosts, money, or precious rare items like Toxicant and Deep Pass Water. You can activate the boss rush as many times as you like be re-entering and leaving the hotel.
Note: The Scribe Ani is a character from the Stardust Crusaders novelization, which has yet to be translated into English.
Final Battle Retake
Requirements: Dio's Mansion has been found, total sum of entire party's FP is over 50
Stay in the hotel with the above conditions fulfilled, and your character can choose whether to go to bed early or stay awake. Head to bed to trigger a sequence of battles and events leading to one of the Everybody Lives endings - see Ending Guide for more details. Be aware that with the exception of one ending that's only accessible after beating the game at least 3 times, none of these endings will allow access to the Developer's Room and New Game + features.
Church of the Dark Lord
In the northern part of Cairo, there's a church for an evil cult that worships a dark god. Unlike the other churches in the game, which will randomly lower bad karma for a 100G donation, this church will raise your bad karma to 10 for 100,000G. You can also check your bad karma here, which is useful if you're going for a secret ending that requires it. If it's 5 or above, you'll see transparent demons, and if it's 10 or above, you'll be able to see them clearly and speak to them. Beware if you attempt to give a donation without enough G, as the nun will simply take all the money you currently have and kick you out, without giving you bad karma.
Range S-M. Appears in a group of 3. You can tell them apart from other automatic Stands because they run away from the protagonist and do not vanish when the radio is turned on. They're tough, and use Ripple attacks, but they have a high EXP yield and also give the highest chance of raising Iggy's FP out of any enemy, so they're worth chasing down.
(Evil) Ripple Warrior
Secret Book Vol. 12
These enemies only appear if you return to Cairo after finding Dio's mansion. Range: S, and appears either alone or with Overdrive x2 - the ones that have Overdrives with them will jump around on the map. The drop is rare, but teaches the Ripple Gale skill and will make the boss battles to follow much, much easier.
BOSS: Hol Horse
0 (He forgot his wallet at the hotel, remember?)
Range: M. Vulnerable to Darkness, Confuse, Sleep, and Berserk. If the player is a girl, he'll start with HoldBack status. Doesn't have much attack power, but will debuff your stats. His Homing Shot also inflicts Pursued status.
BOSS: Pet Shop (Stand: Horus)
Range: M. Stats aren't that high, but almost all of his attacks can freeze you. If you're fighting with Iggy alone and he gets frozen, you're almost 100% doomed, so unless the protagonist with you, it's probably better to just run unless Iggy's levels are high enough to knock him out in a few turns. Vulnerable to Darkness and Poison.
BOSS: Ice Missile
5 appear with Pet Shop - 2 at range S, 3 at range M. 2 turns after appearing, they'll use a self-destruct attack and crash into you. Damage isn't anything to worry about despite the number, but they'll likely inflict Dizzy and make you lose a turn. They'll regenerate if you defeat them, but not if they attack. (You won't get what little EXP and items they drop, though.) Weak to Fire.
Starts out at range S. Invincible to all non-close-range attacks, but really easy to inflict BlowBack on. This version has the Tower Needle attack from the Hard Mode Tower of Gray, which inflicts 1HKO with high accuracy, so watch out for that.
Dark Blue Moon
Range: M. Weak to Electricity. As long as you have decent mid-range attacks, he's a pushover.
Starts out at range M. Is invincible when hidden in the wall, and has an Attack stat comparable to Dio's. If you want, use target-all moves before his Hook and Propeller get a chance to attack. Vulnerable to Berserk, Confuse, and Sleep.
Range: M. Appears with Forever, who can revive it if defeated.
Range: M. Appears with Forever. Regenerates if you defeat it, but not if it self-destructs by crashing into you.
Range: M. Immune to all status effect except BlowBack. Will use Grudge Power to buff itself, so don't let this battle drag on too long.
Range: S. High defense as always, can scatter slime to absorb HP, and has Push It To The Limit which he uses to heal and buff himself. Doesn't morph into other characters like he did in Singapore. If you have insta-death attacks, spamming them might wrap things up quicker than trying to whittle his health down. He's also vulnerable to Darkness, so use the UV Lasers if you have them.
Range: L. Will use Push It To The Limit if your average level is 50. Has insta-death techniques and will debuff your Power and Speed. Other than that, he's not that tough, so take advantage of this battle to recover in preparation for Hanged Man.
Hanged Man (Mirror)
Invincible, although he can be inflicted with status effects. 'Goes for the jugular' a lot to inflict 1HKO. Use your stock of Phantom Bloods wisely.
5 appear with Hanged Man, 2 at range S and 3 at range M. Defeating one of the drums will end the battle, but unlike Lovers in Karachi, this drum is random. Has attacks that inflict Bleeding and BlowBack. All attacks are physical, though, so if you buff your durability with Joseph's Ripple Hair Attack or Iggy's Sand Wall you'll have an easy time of it. Save your recovery items and go all-out. The drums are vulnerable to BlowBack, Dizzy, and Surge, but it's much better to use target-all attacks then to take them out one-by-one.
Range: S. If your average level is 50, she'll use Push It To The Limit. Honestly, not that big of a deal compared to Hanged Man. Use this battle to recoup some HP and SP from the previous fight before you defeat her.
Wheel of Fortune
Range: M. If your average level is 50, he'll use Push It To The Limit. Will inflict Dizzy on the entire party and use strong attacks that inflict BlowBack. Has high a Power stat and will buff his Speed into oblivion. His other stats aren't all that high, but he'll still take a while to defeat. Conserve your recovery items here.
Range: L. Mostly recovers and defends, but sometimes uses attacks that inflict Fear. High defense for a long-range enemy.
Range: L. Pretty much invincible. Will revive the Corpses and use control moves on the party. Attacks are pretty strong too, so don't let your guard down.
Range: M. 3 appear with Enya, and Justice can revive them infinitely. Attacks are stronger than you'd expect, so use target-all moves to take care of them quickly.
M: Experience Tablet
3 at range M, 5 at range L. Defeating one will end the battle, but unlike the last fight, this is random. Best to use target-all attacks to damage all of them at once, but if you have strong single-target moves, testing your luck is still a viable strategy. Attacks are mostly physical, and they'll recover a lot. Every turn, the fakes you defeat will regenerate with 60HP. Weak to Fire and Light.
Range: L. If your average level is 50, it'll use Push It To The Limit. Mummy status will negate your recovery, and its Heat Ray does a ton of damage. It's also unaffected by status ailments. This'll be a long, tough battle, so make sure you have recovery items stocked up.
Range: S. If your average level is 50, he'll use Push It To The Limit. If your average level is above 40, he'll also use the Iai Slash. Other than that, you shouldn't have too much trouble if you keep an eye on your health and use close-range moves. Slightly vulnerable to Bind.
Range: M. If your average level is 50, he'll use Push It To The Limit. He's way tougher than the one on the island - he has high attack power, and most of his moves inflict Dizzy. He's weak to Fire, though, so if you're with Abdul, he'll go down in a flash.
Range: S. Mostly uses physical attack, and can also self-destruct by crashing into you if your average level is above 40. If she does so, she cannot be revived. Weak to Fire and Light.
Range: M. Mostly uses physical attack, and can also self-destruct by crashing into you if your average level is above 40. If he does so, she cannot be revived. Weak to Fire and Light.
Range: S. If your average level is 50, she'll use Push It To The Limit. Invincible when hidden, during which she'll heal herself, and she 'goes for the jugular' to 1HKO you quite a bit. Also has attacks that target the entire party.