There's some confusion here. DCUO does not allow players to play as any role they want using any power they choose. They are limited by the pairings of the roles to their powersets. 1) There are 4 roles. DPS, Tank, Controller, Healer. 2) every powerset can access the DPS role. 3) the other roles are arbitrarily only available to specific powersets. 4) if you choose a power, understand the role it has access to. 5) alternatively, if you are interested in playing a specific role type, you are limited to powers that offer access to that role. The powersets / roles are: Tank Powers: Ice Fire Earth Rage Atomic Control Powers: Gadgets Mental Light Quantum Munitions Healer Powers: Nature Sorcery Electricity Celestial Water For example; it is not possible to be an electric or sorcery tank. It is not possible to be an atomic or water controller, and it is not possible to be gadgets or fire healer. The game is not programmed to support the other role's features from other powersets. There's no way to heal with non healer powers. There's no way to taunt with non-tank powers (there is a difference between taunt and generation of "hate"). Tanks can "control" targets but in this game the controller's primary function is to generate power and there is no way for non-controllers to generate power. For more information on powersets and roles click here. For the answer to your specific question about what artifacts to use as a tank, that depends which powerset you chose and your personal playstyle. A good starter can be found here on Obsidian Chill's YouTube channel. The most popular and practical Tank artifacts are Manacles of Force, Everyman Prototype and 7 Mystical seals.
But to expand a bit, Tanks do more than just stay alive. Taunts, pulls, holding adds/bosses, etc. for which we have specific skills, plus a considerable increase in defence. In the absence of an actual Tank, I'd imagine the DPSs would start getting annoyed when they're going down like flies because the Healer can't perform these roles. As a stop-gap in the absence of a Tank, perhaps it'd be better than nothing.
For Sorcery Damage: 1. Grimorium Verum 2. Source Shard 3. Whatever you want: Strategist, Solar Amplifier, La-Mort
