Dragon Scripts, one of the required items, can be obtained primarily by slaying bosses in the nether. Many of these bosses require a small group to handle efficiently, so keep a few friends handy.
You can exchange 40 Dragon Scripts for a blank Tome of the Dragon at /warp endgame.
Elemental Dragons are the ultimate group challenge, putting your skills and gear to the test in exchange for essential treasures and power. Anyone can summon an elemental dragon using a Tome of Dragon Summoning, which can be forged by collecting its necessary items.
Dragon Soul Emeralds
Another required item is Dragon Soul Emeralds. These dragon souls have a small chance to drop from final bosses of hard dungeons, or sometimes from Dragoons, which may patrol some of these hard dungeons.
Combining a Tome of the Dragon and a Dragon Soul Emerald in a crafting window will create a Tome of Dragon Summoning of the element matching the used Dragon Soul.
Activating a Tome of Dragon Summoning in the end realm will summon an elemental dragon, who will attack you immediately. Each type of elemental dragon employs many different attacks, which will need to be learned and mastered in order to defeat them.
If you can manage to defeat an elemental dragon, your effort will be rewarded with very unqiue loot ranging from trinkets and gear to crafting materials.