The Ancient King Party-level Dungeons were open to all now, so even if Tyrant Sword King the Fifth completed it, he would not get the first kill prize.
However, the first kill did not seem to matter to Tyrant Sword King the Fifth at all, because all he had been doing lately was attempt the Lostland Instance Dungeon over and over again. If anything, it was his lack of progress that was getting to him — he had yet to get past the second boss.
Along the way, Tyrant Sword King the Fifth had looked to countless people for assistance. He had even invited the Fluttering Snow Continent's number one main tank, Amber Sword Heart, but even that did not help. He still could not defeat the boss.