Soul fragments are obtained and used in the members-only Soul Wars minigame. They are used on the Soul Obelisk to reduce the Slayer level requirement to attack the avatars: Avatar of Creation and Avatar of Destruction. The initial slayer requirement (the requirement is represented by the avatar's level) to harm the avatar is 100, rendering it invincible to all slayers. Capes are not allowed into the arena, so therefore, you may not bring your slayer cape into the arena, in an attempt to boost Level 99 Slayer to Level 100. Each shard sacrificed to the Soul Obelisk will lower the Avatar's level by one.