Sheild Of Arrav

Official quest description: Varrockian literature tells of a valuable shield, stolen long ago from the museum of Varrock, by a gang of professional thieves. See if you can track down this shield and return it to the museum. You will need a friend to help you complete this quest.
Release date: Unknown
Start: Varrock library. Talk to Reldo, the librarian or Charlie the Tramp.
Difficulty: *****
Length: Medium
Members only: No
Requirements: A trustworthy friend or partner, and if you want to join the Black Arm Gang, the ability to kill a level 26 enemy.
Items needed: 20 coins if you want to join the Phoenix Gang or 2 coins and 2 Phoenix crossbows if you want to join the Black Arm Gang.
Monsters to kill: None
Spoiler warning: Plot and/or ending details follow.
edit Walkthrough
It is important at this time to decide which gang you wish to join. This choice is important for two reasons:
You need a member of the opposite gang to cooperate with you in order to complete this quest.
This choice will show up for future quests if you decide to become a member. Most notably, the Heroes' Quest has gang related activities where item trading between both gangs is also an important feature.
Being a member of the Phoenix gang is more complicated and expensive to complete, but gives you a larger headquarters and access to the Phoenix crossbow directly. It also requires you to defeat combat level 23 personality in close combat in order to help the Black Arm gang member complete his tasks.
The Black Arm gang is recommended if a player has lower combat levels, and is a cheaper alternative with close cooperation from a Phoenix gang member.
Phoenix Gang
Talk to Reldo, located in Varrock's library, in Varrock Palace. Ask him about a quest and he will tell you there's a book on something in the library. You have to now search the book case with a blue book. When you've found it, read or skim through it.(The book is blue.) After you've read the book, talk with Reldo and ask him where you can find the Phoenix Gang. He doesn’t know, but he says the fur trader Baraek might.
Baraek is located in the centre of Varrock. He buys and sells furs, and his stall is marked with an icon of a bear fur. Talk to him and ask about the Phoenix Gang. He will want you to give him 20 coins for info. Give him 20 coins, and he will tell you it is located in the south-east corner of Varrock.
The hideout is near the south-east corner of Varrock. It is a bit south of the rune shop. Look for a red exclamation mark (!) on your map to find the hideout. When you've found the red exclamation mark, you will see a ladder. Climb down it to enter the Phoenix Gang's hideout.
Inside the hideout, talk to Straven. If you ask to join, he will mention the Varrock Herald newspaper. This is a cover up. There should be an option that you can tell him that you know who he is, that he is part of the Phoenix Gang. If this option isn't there, go back to Baraek and ask him about the Phoenix gang again.... you missed getting all of the information from Baraek.
Straven will want you to kill Johnny the Beard (combat level 2). He is located in Varrock's Blue Moon Inn. This bar/restaurant is located near the south entrance of Varrock. Go inside the bar and find Johnny the Beard and kill him (he may need to respawn). It should be noted that some players may just attack Johnny "for fun" or to simply be annoying. If that happens, you might want to switch worlds and find a world that doesn't have this happening.
Johnny will drop a report which Straven wants. Grab the report and bring it back to Straven. Talk to Straven while having the report in your inventory, and you will become a Phoenix Gang member allowing you to enter the hideout. Straven will also give you the Weapon store key. Do not worry about the thieves walking around if you are at a low combat level; they're not aggressive to any players as long as you don't attack them first.
Look around for a chest in the south-west corner of the hideout to find one half of the Shield of Arrav. You can only grab one shield at a time.
Black Arm Gang
To join the Black Arm Gang, talk to Charlie the Tramp located near the south entrance of Varrock. Ask him what’s down the alley, and he’ll tell you that it’s the Black Arm Gang’s hideout. Go down the alley and enter the building. Look for a woman named Katrine and talk to her.
Tell her you know about her gang and that you won't give your source. Tell her to prove that you're trustworthy and she will give you a task to join her gang.
Katrine wants you to steal the Phoenix Gang's stuff. She wants 2 of their crossbows. However, you will need a partner or friend to join the Phoenix Gang for this part of the quest.
When your partner/friend has joined the Phoenix Gang, he/she will be given a key. Ask for this key. When you have it, go to the Phoenix Gang's hideout outside. Look for a door that is locked. When you've found it, use the key with the door and climb up the ladder.
You will have to kill the Weaponsmaster on this floor. After that take 2 Phoenix crossbows. Once you have them, go back to Katrine, and you will become a member of the Black Arm Gang. Go upstairs in the hideout and look for a cupboard, which contains one half of the Shield of Arrav.
Finishing Up
Take your half of the shield to King Roald. He will say that you need a certificate for the reward and that you need see the Curator in Varrock Museum, north of the east bank. Go and see the Curator, then use your half of the shield on him.
When you talk to the Curator, he will give you 2 halves of the certificate. Your partner, who has the other half of the Shield of Arrav, will get the other halves of the certificate. Trade 1 half of the certificate with your partner for the other 1 half. When you have both halves, use one of them on the other, to get a full certificate.
Take that certificate to the King to get your reward. Quest completed.
Notes
If a player cannot find someone to trade the certificates with, they cannot finish the quest.
If a Phoenix Gang member tries to talk to Katrine, she spits on them and does not allow them to join the gang. If a Phoenix Gang member tries to kill the Weaponmaster to obtain the crossbows, the player is told that he or she cannot attack a fellow gang member.
A Black Arm Gang member can enter the Phoenix Gang Weapon Storage with a key from a Phoenix Gang member.
If working with additional players who want to get the half of a certificate from you, it would be wise to take the half certificates to the bank, store them, grab another shield half from your respective gang house and present it to the Curator. There is no practical limit to how many certificate halves you can have, but it is a tedious process going back and forth to the Curator and the gang stronghold. You can have only one shield half in your inventory at any given time. Also, keep in mind that once you have completed this quest, you can no longer obtain the shield half any more, although you can continue to keep certificate halves in your bank account indefinitely after you have completed the quest or trade for them with other players.