Zogre Flesh Eaters

Start

 * Speak to Grish, located at Jiggig (south of the Castle Wars entrance). He will talk about Zogres (Zombie ogres) coming from the ground and making people sick. Ask if you can help, and progress through the conversation. Grish will give you two Super restore potions and three Cooked chompy birds.
 * Talk to the Ogre guard to the east. After mentioning Grish, he will remove the barricade to allow you inside the Zogre-infested area.
 * Run east to a set of stairs going downward. Take these stairs.

The cave
Note: You may now (or have already) been diseased. From now on, make sure you carry super restore potions with you! The disease will temporarily reduce a random skill by up to 10 levels every minute or so!
 * Proceed northwest to an area with a blackened floor. There will be a short cutscene.
 * Search the skeleton, a zombie will appear and attack. Kill it to obtain a ruined backpack.
 * Open the backpack to obtain a tankard, some rotten food and a knife.
 * Search the broken lectern. You will find a torn page that contained a spell.
 * Attempt to search the coffin nearest to the skeleton, and then use a knife on it. The lock should unlock. Try opening the coffin (it may take a couple of tries). When the coffin is open, search it to obtain a Black prism.
 * Backtrack and exit the cave, running back to the barricade.

Yanille

 * Proceed to Yanille.
 * Go to the Dragon Inn and use the tankard on the bartender. The bartender will explain that the tankard belonged to Brentle Vahn, a not-so-moral customer who had been seen with a shady wizard.
 * Talk to Zavistic Rarve in the Magic guild. If you don't have the required level to enter the guild, ring the front bell and Rarve will appear outside. After seeing the prism and torn page, Rarve will tell you to talk to Sithik Ints in the guest house north of the guild.

Incriminating Sithik

 * Proceed to the top floor of the guest house. Sithik is in the west bed. Talk to him, and he will deny any connection to the Zogres. When you raise allegations, Sithik will challenge you to find facts. We need to show a picture of Sithik to the bartender to see if he was the wizard seen with Brentle.
 * Search the drawers, the cupboard and the wardrobe. You will find a Book of Portraiture, a Necromancy Book, papyrus and charcoal, and a Book of 'h.a.m.'.
 * Read all three books.
 * Use the Book of Portraiture on Sithik. He will recommend trying portraiture.
 * Draw a portrait of Sithik by using the papyrus on Sithik. When you're done, use the portrait on Sithik. If Sithik appreciates the "truth" of the portrait, than the portrait isn't realistic enough and you should try again. Search the drawers for more papyrus and sketch him again. With an accurate portrait, Sithik will appreciate the "honesty" of the portrait.
 * Take the portrait and the tankard back to the bartender. The bartender will recognise Sithik and will sign the portrait as an affidavit.
 * Talk to Zavistic Rarve while holding the Necromancy book, the Book of 'h.a.m.', the tankard and the signed portrait. This will be enough evidence for Rarve to give you a potion, which he will instruct you to use on Sithik and then leave the house.
 * Use the potion on the cup of tea on top of Sithik's dresser.
 * Go downstairs and back upstairs. Sithik will have turned into an ogre.
 * Talk to Sithik, and he will confess. Obtain answers to all three questions.

Making Relicym's Balm
Having Relicym's Balm on hand in the final fight will help tremendously. It is your choice to obtain this now; however, the quest can be done without it. The balm is also tradeable.

Relicym's Balm is made like any potion, it uses Rogue's purse as herb and Snake weed as secondary ingredient.

It is HIGHLY recommended to make this and give it to Uglug Nar. This will give access to a store selling 100 Relicym's balm(3). The store also has 100 Achey logs, 10 Bowstrings, 10 cooked chompy and 5 knives in stock.

Making Brutal Arrows
Brutal arrows are the best way to kill Zogres, and shooting them from a composite ogre bow is the best strategy in the final fight. It is your choice to obtain them; however, the quest can be done without it. To make the arrows, cut down Achey trees. After, fletch them into Ogre arrow shafts (each log will give 2-6 shafts). Then, add feathers to the shafts (Each shaft needs 4 feathers). Finally, to make the Brutal Arrows, use nails (made of any metal), with a hammer in inventory on the Flighted ogre arrow. Each time you do this, it will make six arrows at a time.

Relocating the Ceremonial Grounds

 * Return to Grish and tell him what Sithik told you.
 * Grish will give you a key to obtain access to the ceremonial chamber.
 * Prepare for a rather tough fight. The Zogre (named Slash Bash)that will attack you is level 111 and attacks with both a melee and a ranged attack. Your best bet is to make some Brutal arrows and fire them with an composite ogre bow, Learn to make from Grish. However, this boss can also be killed without too much difficulty using the Magic Entangle/Cast pattern. Prepare according to how you would like to fight, but in any case it is recommended that you bring multiple Super restore potions.
 * Return to the cave beyond the barricade and head west. There will be two successive locked doors, proceed through these and descend the stairs.
 * Proceed to the end of this long, wide room and search the stand.
 * A level 111 Zogre named Slash Bash will attack you. If using ranged, find a safe spot and range the Zogre using Protect from Ranged. If maging, cast Entangle or Snare followed by a wave attack or Crumble Undead while using Protect from Ranged, or simply use the safe spot while protecting from ranged. Fire blast maxes out at 4 against this boss so make sure to bring enough casts. Alternatively, with decent armor (Rune+) you can melee the boss down with little to no trouble. In either case, your prayer will drain very fast so make sure you use Super restore potions when you need them. Once the Zogre is dead, collect the bones and the artefact that he drops.
 * Return to Grish for your reward.

Reward
Bonus: Take the Black prism to either Zavistic Rarve for 2000 coins, or take it to Yanni Salika in Shilo Village for 5000 coins.
 * 3 Ourg bones which reward 140 prayer experience each
 * 2 Zogre bones which reward 22 prayer experience each
 * 2,000 Fletching experience
 * 2,000 Ranged experience
 * 2,000 Herblore experience
 * Ability to make Relicym's Balm
 * Ability to fletch Comp ogre bows and Brutal arrows