Guide:Completing the Bestiary

This guide describes how to complete 100% of the Bestiary in one world without bringing anything from another world and assuming you go through a classic Walkthrough and you are in a world created in 1.4 without special seeds and not in holidays.

Early game
The early game is quite standard, you don't have to do anything special and you way want to get gear to continue. You will just have to defeat every pre-Hardmode bosses and crush at least one Shadow Orb or Crimson Heart to trigger the Goblin Invasion.

Getting the other Evil
You will need to get some Crimson in your world if you are in a Corrupt World or some Corruption if you are in a Crimson World and it should be easier to get them while you are still in pre-Hardmode

The Cemetery
To complete the Bestiary, you will need the other evil in your world. To do that, you need to gather at least 6 Tombstones created after your deaths or after your NPC deaths if you are in Hardcore. Place the 6 tombs around the Dryad to buy her some Corrupt Seeds/Crimson Seeds. If you didn't beat them already, profit being in a cemetery to kill some Ghosts, Maggot Zombies and Ravens. You will see some Maggots spawn after killing the Maggot Zombies and some Rats while in cemetery, walk near them to complete the Cemetery part of the Bestiary.

Other Evil surface
Now you have some evil seed, plant them in a place where there is a lot of uncorrupted grass, wait a bit and you will be able to gather some Vile Mushroom/Vicious Mushroom. You can now transform them in Thrown Powder to spread the evil even more. If you prefer Thrown Water, covert some sand with the powder so you will be able to make them. Keep some powder or water in a chest in case that your evil is converted when the Hardmode begins and beat the Eater of Worlds / Brain of Cthulhu

Checking the rare creatures
Some rare creatures are even rarer in Hardmode so you should beat them before, you could increase your chances of seeing them by using a Water Candle / Battle Potion / increasing the spawnrate in Journey mode :
 * Giant Worm (165) in Underground layer
 * Nymph (179) in Cavern layer
 * Tim (182) in Cavern layer
 * Doctor Bones (242) in Jungle at night
 * Devourer (311) in Corruption

Early Hardmode
Once again, you should focus on your progression on early Hardmode, beat the Goblin and Pirate Invasion, Queen Slime and at least one Mechanical bosses

Completing the biomes
Now you have enough stuff, you should be able to complete the different biomes. You should get a Clentaminator, some Green, Blue and Purple/Red Solution and some powder/water of the other evil

The snow biome
While you are in surface, capture two Penguins, kill monsters at night and during rain until you've seen the 7 critters and monsters (number 92+) Once you met all of them go underground. Use your Clentaminator with green solution if the Ice biome is not pure then start throwing your powder or water around to corrupt the biome with the other evil then wait around until you beat Pigron(purple if it is Corruption, red if it is Crimson). You can then use the other solutions to transform the biome again and kill the other two Pigrons. If your underground snow bestiary is not complete, spend some time there with water candle and battle potion to beat them.

The sand biome
This part should take some time as you will need to convert a desert in 4 parts : one Hallowed, one Corrupt, one Crimson and one pure, then wait for a Sandstorm. There are four kinds of Sharks each can spawn in one part of your new desert during Sandstorm. You will have to beat each in order to complete the Sandstorm event in the Bestiary. You should also beat each type of Mummy this way. Now the desert, sandstorm, corrupt desert, crismon desert and hallowed desert should be complete. If not, you should wait longer in this zone or put some water in it if number 96 or 97 are missing (these are oasis critters). Once you are done, go to the underground and free the Golfer if you didn't already do it. Then do the same as for the snow biomes to create corrupt, crimson and hallowed places. There is a ghoul for each to beat, and you will have to beat a Lamia in Corruption/Crimson and one in Purity/Hallow. After that, you should have completed the 4 underground desert bestiary parts, or if not, it's just a matter of time.

The rest
The rest shouldn't be hard and now you should have completed many parts of the Bestiary :
 * Party
 * Windy Day
 * Rain (if 338 (Rainbow Slime) is not unlocked, convert a place into Hallow, place a non Hallowed floor and wait during rain)
 * Graveyard
 * Underground
 * Granite
 * Marble
 * Underground Mushroom (except 91 (Truffle Worm))
 * Spider Nest
 * Snow (except 23 (Cyborg and 25 (Santa Claus), if 22 (Tax Collector) is not there, go free him)
 * Underground Snow
 * Desert
 * Underground Desert
 * Sandstorm
 * Jungle
 * Meteor
 * The Underworld
 * The Corruption
 * Underground Corruption
 * Corrupt Ice
 * Corrupt Desert
 * Corrupt Cave Desert
 * The Crimson
 * Underground Crimson
 * Crimson Ice
 * Crimson Desert
 * Crimson Cave Desert
 * The Hallow (except 109 (Prismatic Lacewing) and 507 (Empress of Light))
 * Underground Hallow
 * Hallow Ice
 * Hallow Desert
 * Hallow Cave Desert
 * Surface Mushroom (except 21 (Truffle))
 * Goblin Invasion
 * Pirate Invasion

If one is missing, go in the biome or create it then spend some time in it

Blood Moon
Now you have completed the different biomes, you can continue your progression and beat the others Mechanical bosses if they aren't already dead. Capture two Bunnies and two Goldfishs, take three evil powder of each kind then convert one Bunny, one Goldfish and one Penguin to each evil by throwing one powder at them then kill them. It is then time to fish. Summon a blood moon with Bloody Tear or wait for one to happen and start to fish. You will have to kill at least one Wandering Eye Fish, one Zombie Merman, one Hemogoblin Shark, one Blood Eel and one Dreadnautilus to complete the Blood moon part. Use the Chum Caster as soon as possible to fish them more easily.

The Endgame
Now you can continue your progression by killing Plantera, Empress of Light, Golem and Duke Fishron. Complete the Dungeon, the Temple, Underground Jungle, the Solar Eclipse, Ocean and beat the Old One's Army by doing so. You must also complete the Martian Madness by finishing one event and killing one Martian Probe. Note that the Martian Probe spawn chances are highly increased when you are near a Water Candle.

Halloween
With your new gear, you should be able to beat the 15th wave of the Pumpkin Moon. Once it is done, you will have one day of Halloween. There are 11 creatures to unlock : go directly to the Caverns, increase the spawnrate because you will have to kill three different skeleton in costume, which are quite rare. Once they are beaten, go in the surface again and place a cemetery if it is the day. You will have to beat one special form of bunny, one of slime, two Demon Eyes, three zombies and Hoppin' Jack which spawns at night.

Christmas
This one will be tougher, you have to beat the 20th wave of the Frost Moon to unlock one day of Christmas. Once in Christmas, beat as many monsters as possible, there is one form of bunny, 4 of slimes and 2 of zombies. Open as many Presents as possible as you will have to quickly start and beat the Frost Legion. If it is still the day, Santa Claus may spawn this day. Else, you will have to beat the Frost Moon again to make him spawn.

The end
The only monsters remaining are linked to the Lunar Event : Beat the cultists, the four pillars then the Moon Lord and the Bestiary will be 100% complete. You can now buy the Universal Pylon to the Zoologist.