The Nameless wants to set a special challenge for you. As you speak with him, he explains, that he has found a new method, to directly teleport others to bosses from RuneScape. As he cannot use it on himself, he needs someone to test it on. You will then get a very long list of boss monsters ranging from level 75 to 1650. He will offer you to get teleported to them, and you have to defeat them alone. He also counts the boss you get teleported to, as a slayer-task, so the Full Slayer Helmet will work on them. Should you die during while fighting one of these bosses (only if teleported to them by him), you will respawn to the quest start point, losing none of you items (except the food and potions you used up). The bosses are instanced, which means, that no other player can interrupt you (ac