There's 2 Critical weapons Quests in game.

1: The Egypt quest for King Tut's weapons, They are the Accuminate Halberd +50 Atk and 14% hidden critical Chance and Thut's Wand +40 Matk and 14% hidden Critical Chance.(The quest after you finish it and get to the part where you pick which weapon you want it says on the description 14% Critical chance.) Heres how you do the quest and sorry for no pics i need to do an alts crit weap and ill post em up.

Start off in egypt outside the hotel there's a guy complaining or rather wondering why 1 "Certain" person can work all day and night without eating or drinking. After talking with this guy take the right portal in Egypt, youll be taken to a lil plain with burning caterpillars and mantises. Dont go to the middle portal take another right and more woods. After that you should see a "?" on the bottom of the screen go there. Talk to the"Certain" guy and youll find out hes a martian. This is a semi hard battle its against 2 martians around 4-5k hp a wind and a water i think. Beat em and go back to the guy you talked to first. Yay 1 prequest done.

2nd prequest you will need 1 magnet stone and 3 magnets. You can make magnets if you have money and cypress to spare by buying silver rings in Inchon(aka korea) and compounding em with cypress. About 16 magnets make 1 magnet stone so either fish/make/or buy 19 magnets. after you get all 19 make a magnet stone with the grinding eq and 16 magnets and some iron material i forget how much. Once your done get a boat and head down the pier to the Egypt Desert. once tehre keep going down to the bottom right corner of the map there youll meet that same martian you beat earlier. he needs 1 magnet stone and 3 magnets to go home, give them to him and youll get a baked potato(which takes all sp away from your opponent not useable in PK[i think]) and a forgotten scroll(which lets you change 1 point from your own stats to another) Awesome 1 more prequest done.

3rd prequest: You will need a Aether space craft and save your record in egypt before this. Get a team ready and get in your aether spacecraft and go to mars. once there youll go find two odd looking stones there both battle's with semi hard but HARD hitting martians. once your done with both go to the bottom left corner and guess who you find again? That same martian you helped in Egypt. He gives you the mars Aerolith and a star.

4th prequest(not sure if it is part of it or not. I did it anyway.) The acrobat quest. a group of acrobats are being harassed by local "law enforcement" more like bullies if you ask me. Beat them and boom your done.

Actual Crit quest: Ok i hope your ready for a long battle The requirements for this is to be Lv 70+ and you have to had done the GS quest(otherwise known as the fairy's revelation.) Remember that pillar by the acrobats you saved? Have the Mars aerolith and click the hole in the pillar and boom your in Tut's tomb. Once in go through the top right portal and youll be in a room with a puzzle. Read the paper in the room and do the puzzle pretty easy. Now last and finally the battle. I suggest a lv 150+ or RB team for this cause they even made my Shio21 Acc spawn in this quest and he has 2.4k hp. you have 8 monsters at first 4 mummies in the back and 4 scorpions. the mummies seal so take care of them first in this order: Earth, Wind, Fire, and Water or Wind, Earth, Fire and Water. After you beat these mummies another WEAKER version of it takes its place kill it quickly and move on to the next stronger element mummy. After the mummies time to take out those pesky and damaging Scorpions.Same order like the mummies but instead of fighting a Weaker version of it you fight something stronger. Remember those bullies you fought helping the acrobats? you fight them again but only MUCH MUCH stronger. Again follow the element order and take em out 1 by one. Once there all gone YAY YOUR FINALLY DONE! now chose your weap and spawn out of there. These weapons are socketable so you can put in a diamond and can be even stronger than the IM weapons like Sky sword, Lord Sword, Light Wand, Polished wand and so on and so forth with a good diamond just not in the sense of crit its ALWAYS 14% crit.At max +8 a sky sword has 66 spd and 66 atk add a violet diamond to the accuminate halberd and hey you have +68 atk better than sky sword right?
That's one of the in game Crit weapons.

The other Crit weap is the Dragon sword and dragon soul wand That you get from the Dragon soul skill quest.Even tho i did that quest i dont wonna go into detail sorry, but the stats are +30 spd and +15 atk(correct me if im wrong) and 14% crit for the dragon sword the wand is similar but i forget the stats ive havent done Ds for my mage yet and im not planning to but the stats are similar and Yes there socketable.

Hope this answers some questions.