First Dragon Quest/Spoiler

Required Equipment

 * Rope, Shovel

Collecting Treasures
First, you must collect treasures from around Tibia. They are located in a variety of dangerous places, some of which are accessible at any level but some are dangerous and require high levels.
 * Edron Old Fortress, here.
 * Darashia Dragon cave, here.
 * Farmine Dragons, here.
 * Carlin Ghostlands, here.
 * Yalahar north west Grim Reaper cave, here.

Knowledge Boss

 * Visit the NPC here.
 * He will ask you 3 questions, the answers are Tahmehe, Ishara, and Svir respectively.
 * You may now enter the portal and kill the boss within.

Life Boss
To gain access to this boss you need to walk into 3 special areas.
 * The Fire of the Suns blessing tree, here.
 * The Oasis in Ankrahmun desert, here.
 * The stone sculpture north of Carlin, here.

Note: It is currently unknown what you must do once you've killed all of the bosses, however there are a claimed total of 19 treasure chests throughout Tibia, which offer various rewards.