Looks like we are getting an option to practice fights in a dungeon or raid as a part of the heavensward updates. This made me think, "Could we get a boss attack mode?" Like a Colosseum mode (FFVII) I would love that! Either Solo, Duo, 4 man, 8 man, or 24 man. Even if it was just solo/duo to start, it would be so much fun to have a ladder ranking on how far you get with constant streams of enemies that get increasingly harder.

The specifications are already planned for the "practice mode" for raid dungeons. However, the implementation won't be simultaneous with the release of the raid dungeon itself, it will be a little behind. (Yoshida)
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