Waste an opportunity
Whether the site manager would open the boss battle tonight, I wasn't sure. After a while without a reply, I just went to read a novel. When I checked the forum at 9:30, I saw a post that the manager had just made. I thought it was just starting, so I quickly entered the game, but I was still late and only managed to play 3 rounds, though I did get to hit the last bit of the boss's health.
