Thanatos Tower
Floor 2 - Hall of Chains
Overview
This fight is very simple, just blow this boss up and collect some keys!
Phase 1 - Defeat Ancient Puppets
Ok ok, this isn't much of a "phase" but you need to kill these mobs in order to spawn the boss. The boss will always spawn in the center of the map and will not move.
Phase 2 - Focus Tesseract until 20%
Yes it's really as easy as that. While you're doing this avoid the huge circular AoE's that appear around you, they explode. There are also gravity wells that pulse damage that you can destroy to stop this effect but as long as you're not standing it them it's not threatening.
Once the bosses HP reaches 20% he will become invincible and start the final phase.
Phase 3 - Gather Keys
Key shards will spawn around the map and you must collect 5 of them within the next 120 seconds to complete the floor or you wipe. Extremely easy fight, not worthy of a guide!