Invictus Warriors is one of the bosses that you need a certain weapon in order to enter & fight it, such as an Invictus Scepter, Invictus Spitfire, or an Invictus Sword. This is the only boss that drops Inga Items such as Inga Body, Inga Legs, Inga Helm, and Inga Sword. These items are Magic based, and are very good! You can get to the Invictus Warriors using the Invictus Portal. The Invictus Portal is located at Home to the West in the arcade room.
In order to kill these bosses, you must have either Invictus Scepter, Invictus Spitfire, or an Invictus Sword. It is highly recommended that you have 92 Prayer so you can use "SoulSplit"
Invictus Warriors does NOT drop souls, maintaining the common and uncommon drops. Invictus Warriors, along with all other NPC's in Dreamscape, drops the Infinity Key and immortal stone fragments