The world Serpent had 3 jobs, the first one was to ensure the safety of earth before the game finished, the second was to award people that did incredible feats if it judges that the systems reward wasn't generous enough, and third, if they failed the game, that is if all humans on Earth died, it will destroy the planet.
That was what the system had said when the game just started, and from what they were seeing, it seemed that the serpent was doing the second task it had, which was to award someone that had done an incredible feat after the system had not been generous enough.
"A power of a Tier V being."
"Tens of Tier IV beings near it."
"A fog that makes it hard for even the system to glance inside."
"A ship from an unknown hostile civilization."