Elvarg
From Runescape Guides & Runescape Tips
Elvarg is the dragon you must vanquish in order to finish the Dragon Slayer quest. Elvarg is a green dragon and is the only dragon that is non-members. It can't be fought after you defeat it. Wearing the anti-dragon shield is a MUST. If you don't, she can hit 50s on you, and you will lose. You may hide behind pillars and range and mage her. She is not a very strong monster, overall. It is good to wear rune armour, if you are going to melee her. You just need to bring an inventory of food (preferably lobsters), and begin the fight. Level 40s should probably be able to defeat her, if they have the right supplies.

