When it comes to Korean games the random is hell. It's not about new or old players.
The sword can get a player that hit Kzarka one time and the rest of time standing safe.
The same for the player that deal the most damage. If you did not get it, it's simple becouse random isn't on your side.
From all the people that hit the world boss only one gets the sword and everyone equal at it.
Better luck next time.