It's a 1-in-2500 chance for a key drop from every mob in the apropriate biome. If you really want the Vampire Knives, make a farm. Either in the Ocean biome (where you also get Pirate Maps) or in Underground Crimson (where you get Crimson Mimics and Souls of Night)

For the Underground Crimson version, make a large room with the roof high enough that Ichor Stickers can't hit you when you're hanging on the ceiling. Then summon a bunch of the best minions you have (Pygmys if you got the staff from Plantera) while wearing either Tiki or Spooky armor. Some Water Candles and Battle Potions can speed things up. Then you just go down and collect the dropped loot once in a while, to ensure that new drops won't erase the old stuff. My first win against Fishron was using Vampire Knives, a Flask of Ichor, the usual boss buff potions and Turtle Armor. You really need to learn his pattern to have a decent chance, so that does mean you will have to try the fight several times before it clicks. Do note that his pattern changes when he gets to half health. And NEVER EVER drag him out of the Ocean biome, he will enrage and go all murderface on you. His weapon drops are some of the best until you crack the various Celestial Pillars, so it's definitely worth doing.

The same goes for the Lunatic Cultist, but he is the gateway to the Moon Lord, so don't be discouraged that he is tough to deal wih without Pumpkin/Frost Moon, Fishron or Martian Invasion weapons.

With the release of the Linux version, I have finally installed the game, and have determined that the main menu works on my system. I haven't tried to start a game, however.

He ain't lying.

I used to run a mega successful B&B, then envy of all those around me, and the gem of the Keweenaw.

Then I discovered Terraria.

Here is a pic me taken last week, playing Terraria.

Is that actually you???? 0_o

Of course not, I've seen that pic years ago already.

Of course. The question is why he let that other guy put a leash around his neck.

Hmm. I already make a farm. It is considered as crimson biome with its background. But the enemies I farm are mixed with hallow ones (pixies, unicorns, and gastropods). But it should be no problem right ? the requirement is inside the biome... not the biome's creatures. Or perhaps I should make somewhere where it is "more crimson" ?

Ah. So that's why. I dragged it outside of Ocean biome (I read that in guide on the official wiki). It seems it was wrong. But that vampire knives...it seems I really need it to progress the game. I guess I'll just farm more crimson.

Thanks for the tips man.

It's not like Vampire Knives will suddenly make the fight a complete walk in the park, but combined with Turtle Armor they provide good damage and sustainability. You'll still need to dodge a bunch and healing potions are still quite useful.

Yeah, I got lucky the other day. I was farming on surface level near Ocean biome and suddenly martian probe came and initiate the event -also after I updated the version to the latest one with higher chance of Martian Madness. And I didn't expect my home base is perfect for fighting Martian Saucer with its tunnels I use for gardening. I beaten few Martian Saucer and got Cosmic Car (infinite fly !). And yes, I do Meele and one of them is Yoyo. It is really helpful for that event.

Also... I have a question about invasion event. Do they always target the home base based on how many NPC's are there? or are they targeting where the spawn point is ? I tried to took on pirate invasion from the west by made a simple base without bed, few of them appeared and that's it. The invasion suddenly stop and won't continue before I returned home.

You're right. I just got Crimson Knives unexpectedly. I tried to use that in the dungeon for testing it out but almost got torn by horde of enemies there because I didn't dodge much. But... I farm Plantera and Golem more easily after got that thing. and still got beaten easily by Fishron though. I'll just mine more chlorophyte to make Turtle armor again. I used the previous one for Beetle set.

Invasions always target the default spawn point. Which is one reason I don't place my houses there anymore, getting NPCs killed during a randomly spawned invasion is annoying. The Moon Events and Solar Eclipse are in effect on the entire surface, so you'll need an underground lair to avoid them, and in the case of (hardmode) Blood Moon that just means you'll get wraiths all over your base if you stay there.

Oh.. I see. I faced Moon Events and Solar Eclipse in my own "fortress" to avoid NPCs involved in the fight. But for invasion I always faced them in my garden at the side of my houses which make the situation for NPCs safe enough. My house is already too big to move it. So I guess I'll stick to it for the current world.

Also one more question : I faced Pumpkin and Frost moon. But the enemies didn't drop some significant items. Especially the frost moon where they just dropped a lot of hearts. Do I need to face them in certain date (like Frost moon on holiday season) to get more valuable items ?

The drop chance for loot in the Frost and Pumpkin Moon events are based on the wave you're on. Higher wave means higher chance, kill stuff to progress in the waves. To advance at a good pace you need dps more than you need survivability, so the Vampire Knives are a fairly poor option here. This is partially because you need kills to progress and partially because the dangerous enemies drop a bunch of hearts when they die. The sooner you can get to wave 15 (Pumpkin)/20 (Frost), the better for loot purposes.

For Pumpkin Moon wave 15 means guaranteed drops, while bosses still have a chance to drop nothing but hearts and money on Frost Moon wave 20 (though it's a lot less likely than at wave 10).

Hmm. Higher waves huh ? Actually I tried it again using Lunar Events weapon and could only reach around 10 - 11 waves. But I already got something from the Frost Moon event (from the Ice Queen). For the pumpkin moon... still having trouble with the Pumpking. Maybe I'll set another arena/battlefield that more suited for those events.

Anyway, thank you again for the explanation.

Progress log

Spent two hours (minus fishing) building a storage space and sorting stuff. Noticed an Extendo Grip vanished. I must have accidentally sold it. Sigh.

Accidentally bought over 600 planter boxes for dayblooms. Started a daybloom/blinkroot high-yield farm, eveyrthing else grows in an experimental lab in clay pots. Caught and sold two gold animals.

Found a sword shrine. Unfortunately, the sword in it was as valuable as a ticking Rolex bought for a three-dollar bill.

Figured out how SUPERIOR STARFURY works! Turns out the stars fall where the cursor points, not at random. Armed with this knowledge, took out two eyes in one night.

Mined out a meteorite. (Ouch, they burn.) Made the full meteorite set, three space guns (the first two sucked) and a purple sword. Bought an ammo box so the star cannon is an option if I start losing to bosses.

How does anyone build anything in Corruption? Got sick of tweezers constantly attacking while building an arena to fight the tapeworm, barely finished a short platform and went down to smash orbs. Got two mana rings and a musket.

I was actually looking forward to the tapeworm fight, because I generally find Crimson much scarier (and therefore exciting), with the exception of the exclusive boss. Brains are funny, and Cthulhu is funny. On the other hand, despite all my apparent irreverence, the Eater of Worlds sounded awesome, second only to the Wall of Flesh (which made me play Terraria -- I accidentally stumbled onto a brief description of Hardmode).

TL;DR it turned out to be a total wimp. I tried hitting it with the sauna whisk but mostly wasted mana on nothing as it hardly ever rose high enough (plus I had to fight off the regular tweezers). Finally, it reached the platform again and I sliced it apart with SUPERIOR STARFURY.