Guide:Surviving in the Crimson

Surviving in the Crimson is almost impossible for unprepared players, yet it it very essential to the game. Here's what you'll need to do to survive in the Crimson.

Armory Essentials
While the Corruption will try to kill explorers with large chasms, the Crimson uses its harsh mobs to destroy any player who comes in. Because of this, extra preparation is necessary. Tungsten or Silver armor, along with at least 140 health is highly recommended, but you should be able to survive the dangerous enemies as long as you can keep a good distance from them. If you are melee, it pays to have a good broadsword made of Gold/Platinum, or Crimtane from the Eye of Cthulhu. Still, even melee players should have a bow or an agile weapon that can attack fast like the bladed glove or the swordfish because keeping monsters at bay is key. The same standard applies to magic and ranged, as long as you can keep away the enemies, you'll be fine, although for ranged you should try to have flaming arrows or better.

Meet the Pre-Hardmode enemies (and their weaknesses)

 * The Crimera is the crimson-counterpart of the Eater of Souls. They will hover above you, and sometimes swoop down and attack you. Neither the Crimera, nor the Eater of Souls will dare attack you if you are submerged in water. Furthermore, they are very easy to keep at bay because they are susceptible to knockback. However, don't let them fool you, because you'll still want a ranged weapon just to make sure you aren't hit.
 * The Face Monster is like a zombie, except taller, and has lot more knockback resistance. However, its AI is quite wimpy, and if you are cornered, you can simply jump over it. Ranged weapons help a lot with keeping them at bay, so make sure to always carry one around in the Crimson.
 * Blood Crawlers are living nightmares for anybody who encounter them, because they don't have any real weakness. (They're almost immune to knockback when they're on walls.) All you can do to survive against them is hope that your ranged weapon will get it away. However, if there are multiple spiders, make sure to have a melee or magic weapon that can damage them all at the same time.

What to do
The Crimson is an extremely important biome that is crucial to gameplay. The main reason why pre-hardmode players explore the Crimson and its caves is because of the powerful drops gained from Crimson Hearts. To find a Crimson Heart, go inside one of the hills that jet out of the Crimson. As you go in, you'll find many Blood Crawlers and Crimson Altars. Once you navigate through the zigzag-like cave, there will be a large drop. Make sure that you have a Lucky Horseshoe or similar fall damage negating accessory. Grappling Hooks can also be used to cling to walls as an alternative method. Be weary of Blood Crawlers on your way down. Once you reach the bottom, look around. You should see at least one Crimson Heart pulsing in its own little cave. Be sure to look out for organ hearts, not Valentine hearts such as the Crystal Hearts.

If this is your first time in the Crimson, you probably won't be able to mine your way to the Hearts, unless you've acquired a Reaver Shark. (After beating the Brain of Cthulhu, you can craft a Deathbringer Pickaxe, which can also mine through the Crimstone.) Prior to actually going to the Crimson, make sure you have either Bombs or Dynamite from the Demolitionist, or Purification Powder from the Dryad. The hearts themselves can also be destroyed with explosions or purifying powder (mind your blast range), but once you've gotten in there you can also smash them with a Hammer. The first Crimson Heart will give you the Undertaker and some musket balls, along with the message, A horrible chill goes down your spine... This will spawn the Arms Dealer NPC for most players, as The Undertaker (or its Corruption counterpart, the Musket) is the first gun many players obtain. The next Heart broken will drop one of the five Crimson Heart items with the message, Screams echo around you... Do not break the third Crimson '''Heart unless you are ready to face the Brain of Cthulhu. '''It will still drop loot, but it will also spawn the Brain immediately -- be ready to dash for your arena!

Optional Tips

 * Build a Base either at the edge of the Crimson, or actually within it, with whatever resources, crafting stations, or other resources you need. Start with workbench, bed, and a couple of chests, then see what else comes to hand.
 * Even if you don't have a full skybridge or skyrail, running minecart tracks over the Crimson area (above reach from the ground) will let you skip past the dangerous area quickly when you have business beyond it.
 * The central cave of the Crimson Chasms makes an excellent arena to kill the Brain of Cthulhu, once you've fitted it with platforms, Campfires, and other conveniences.
 * Another minibase in here will be handy, especially with a bed to set your spawn in the arena.
 * To summon him in the arena, you can break more Crimson Hearts and dash for the arena (or teleport to the bed), or just use a Bloody Spine to summon the Brain at your leisure.
 * Even if you can't defeat the Brain outright, killing its Creepers will give you Tissue samples and Crimtane ore, eventually letting you make Crimson armor. Once you have that, you can easily survive.
 * If you're on multiplayer, you can gang up against the Crimson and the Brain to make the fight easier.
 * After you have broken a Heart, your world will also start getting Meteorites, which will provide another tier of weaponry and armor.