First Dragon Quest/Spoiler

Required Equipment

 * Rope, Shovel

Beginning Quest
Before you begin killing dragons you must obtain the quest from Tamoril, ask him about First Dragon then Rumours, he will tell you there are descendants to which you will ask about Draconic Incitements and tell him you want to Find the dragons lairs.

Killing Dragons
The easiest boss to access is the "power" boss. To access him, you must kill 200 dragons. These must be dragons and not hatchlings, dragon lords, frost dragons, etc. Once you have killed the required 200 dragons, you may enter the boss inside Darashia Dragon Lords, here.

Collecting Treasures
You only need 5 treasures to get access to the Boss.

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. Once you have collected 5 of the treasures, you may access either the treasure boss located in Edron vampire crypt, here or the boss located in Farmine, here. I cannot remember which.
 * Edron Old Fortress, here.
 * Darashia Dragon cave, here.
 * Okolnir Frost Dragons, here.
 * Carlin Ghostlands, here.
 * Yalahar north west Grim Reaper cave, here.
 * Desert Quest, here
 * Port Hope Dragon Lair, here
 * Draconia, 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 to the east and kill the boss within.

Life Boss
To gain access to this boss you need to walk into 3 special areas. Once you have walked into each of these spots and received the server message, you may access either the treasure boss located in Edron vampire crypt, here or the boss located in Farmine, here. I cannot remember which.
 * 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.