Death Isn't The Handicap It Used To Be: A Guide For ???

So, you've been playing the game for a while, and you've defeated Mom's Heart enough times where you fight It Lives instead; the cutscene shows a blue child sitting up in the chest, smiling at Isaac.

If this has happened, congratulations! You have now unlocked ???, the hidden character of Binding of Isaac! He also goes by XXX in Miniboss battles, and "The Blue Baby" if you get a Game Over.

Out of all the characters you are able to play as in The Binding of Isaac, ??? is one of the more interesting characters. Since the game reveals that he is a mummified version of Isaac, ??? is dead. He has no Heart Containers, meaning he runs on Soul/Eternal Hearts. Any red hearts you might see scattered around the basement are therefore useless. If you pick up items that would grant Isaac a Heart Container, it will instead give ??? a Soul Heart equal to however many the item would normally grant. This also makes any items that either heal Isaac, drop red hearts, or fiddle with Heart Containers useless or less useful with ???. Full Health pills will only heal ??? to 3 Soul Hearts if you have fewer than three Soul Hearts, and the Strength card, which gives you the Magic Mushroom effect for one room, will give ??? a Soul Heart that isn't removed on leaving the room. As Trace500 reminds me, Deals with the Devil will always cost three Soul Hearts. This can get you deals at times, since all the items cost the same, but it's best to have a surplus of Soul Hearts before thinking of doing Deals. You are also able to utilize Eternal Hearts, but not only do they only give you a Soul Heart on collecting two Eternal Hearts/starting a floor with an Eternal Heart, but if you lose all your Soul Hearts, the Eternal Heart is not counted, and you will die. Be wary of this.

Having no health permanence might put you off playing as ???; to begin with, I wasn't interested in playing as ??? either. However, as a trade-off for being dead, ??? gets a very minor attack boost over Isaac, and starts off with The Poop. Granted, not the best thing, but it recharges the moment you clear a room, you can block off passageways, messing with an enemy's pathfinding, and you can sometimes get items from the turds you leave behind.

Being undead also gives ??? a different sort of advantage that Isaac can't access without specific items straight from the get-go. Since you have no Heart Containers, the game assumes you have both full health and zero health, as both types of Challenge Rooms will open once the room is cleared. This also affects items that activate when you have half a heart left; the ♥♥♥♥♥ of Babylon item, which normally only activates when you have half a heart left, will remain active for the rest of a game, giving you a permanent speed and power boost (thanks to Tehpillowstar for reminding me). The Polaroid will always activate on taking a hit, giving you a generous boost to your mercy invincibility. The Scapular will only activate if you run out of Soul Hearts, giving you one last chance in a room before recharging. However, the Cursed Skull, which normally teleports you to the previous room on reaching half a heart, will activate every time you are hit, forcing you to complete rooms without taking damage. This is not the most beneficial thing, but can make for amusing situations with the right item setup.

As I mentioned before, certain items are useless to ???; things like the Yum Heart and Little C.H.A.D. serve only to taunt your undead eyes. However, there are items that will greatly increase your chances of survival, should you find them. The Mitre and Mom's Pearl, a collectible item and trinket respectively, both increase the chances of a red heart being a Soul Heart instead. Having both of them will cause the chance to stack, meaning if you have both these items, you'll be rolling in Soul Hearts before too long.

(this next part is useful to any character)

The Relic and the Book of Revelations go from useful items to indispensible life sources, giving you a Soul Heart every four and six rooms completed respectively. Having the 9-Volt and The Battery will let you use the Book more often, and with the Wrath of the Lamb's new item, The Habit, which charges half of your Space Bar charge on taking damage, you can become nigh-invulnerable until you pass the Depths and enemies start dealing more damage. Of course, if you have The Wafer, which makes all enemies deal half a heart in damage, you WILL be invulnerable provided you don't miss using a charge. The Wafer also has the bonus side effect of messing up Deals with the Devil; have it on as ???, and all deals will only take off half a Soul Heart. The chances are so very low that you're unlikely to get to use this setup, but it's something to remember.

I've also been told of The Nail, and have had some time to try it out. Whilst the Nail does serve as a strange mixture of the Book of Revelations and the Small Rock (and not the Book of Belail as I once thought), I would personally recommend the Book of Revelations if you have the choice. The Book can be used thoughtlessly and immediately, whereas you might want to save The Nail for special occasions, such as breaking an abundance of rocks in The Womb, or as a damage boost against bosses.

If you manage to pick up the Polaroid, you can abuse the blood banks, devil beggars, and sacrifice rooms, taking one hit to use it, and then using your shield to get a few free uses out of it. They normally pay out pretty quickly, giving you a Blood Bag/Portable Blood Bank, a Devil/Angel Room item, or a treasure chest respectively. This also works well with The Virus, rather how it works well with the Book of Shadows, wherein you take a hit of damage, and charge at enemies with wild abandon whilst you're shielded, poisoning anything that dares to be near your pestilent corpse.

Incidentally, if you HAVE the Book of Shadows as ???, be sure to have a full charge if you find yourself in a Devil room. You can save your hearts by using it before grabbing things.

These are only a few of the amazing item combinations you can use with ???, that you wouldn't be able to use with the squishy, living characters. However, there are ways for the other characters to obtain this lifestyle as well. Picking up The Ankh from a secret room promises eternal life. In actuality, it gives you an extra life, of sorts. If you die with the Ankh equipped, you'll be dropped back in the previous room as ???, changing your base stats to match his, and making it unable for you to have permanent Heart Containers. This also messes with the game, since it thinks you are ???, and any major bosses you clear will be marked as a ??? clear instead. This does allow you to cheat the game out of some harder items, but it's much more satisfying to finish the game as ???.

If mummification is too good for you, how about a time-share on the border of life and death? With the Guppy's Paw, you can turn your Heart Containers into three Soul Hearts. Overuse doesn't kill you, but it can leave you with zero Heart Containers, and makes items react much like they would react with ???; Constant ♥♥♥♥♥ of Babylon, prolonged mercy invincibility and so on. This has the amusing side-effect of the game not blocking your ability to pick up Heart Containers. So if you picked up, say, Lard or a Health Up pill, you'll get two or one Heart Containers respectively and live again, instead of two or one Soul Hearts. If you have Guppy's Paw to hand, you'll be able to triple your life bar!

If you manage to unlock ???, don't write him off immediately. Not only does he have potential, you also need him to unlock items on beating final bosses. In fact, one of the rewards boosts Isaac! Defeating It Lives with ??? will unlock, and allow Isaac to start with, The D6, which allows you to simultaneously curse out and ♥♥♥♥ with the Random Number God by changing pedestal items on use.

Good luck, and have fun!

(and if you have any tips to put forth, let me know, and I'll credit you!)