Great Girros greatly resembles a cobra in appearance though walks on all fours like a monitor. It is covered in black onyx scales and has yellow stripes running down the back of its neck. On the side of its neck is a hood with red gill-like organs.
Great Girros has large fangs filled with a paralyzing venom. It just takes a single bite from these fangs to paralyze prey as big as Radobaan. It can also spit a yellow fluid from its mouth that can paralyze prey. Great Girros also possesses the ability to call Girros during a fight to swarm it's prey with a barrage of paralyzing bites. If a Grea Girros' hood is damaged it loses the ability to command or call regular Girros'.
Great Girros can be seen prowling around the Rotten Vale.
Great Girros is an active scavenger that is constantly looking for new corpses to feed on. Great Girros is also surprisingly aggressive as it will attack even Odogaron who is the Apex Monster of the Rotten Vale. Great Girros will fight any monster it can swarm with regular Girros.