You may have heard of the Grand Dragon giving a lot of exp points. Well if you're an adventerer like myself you would discover that there's an island. Where a fiend called Yew waits. They come in either on themselves or in groups of up to 4. They are very hard and you really need Doomsday and armour that protects from it. You will kill them eventually and once you have you'll get more exp points than the Grand Dragon gives you.