Just like Boss Strikes, this Boss Event is different and more adopted to the idea I had from other game like NIKKE and Elsword
During the event there are a boss with crazy inflated HP where the whole guild have to fight together to kill it. Lets say each member have 3x attempts each day to deal damage to the boss. Once the boss dies, the boss would respawn with increased level, more hp and additional difficulties like more attack patterns and such. Once the event ends, everyone gets the reward depending on how far each guild has progressed.
In NIKKE there are a strong boss at the final level/stage with literal infinite hp and the reward would be changed from basing on the amount of boss kills that the guild has succeed to do to total damage dealt to the boss.
So it will be just more into single-target fight aspect instead of wave-based/AoE-dmg-based fight.

