Gronos is the third High Krawl that Rallen faces. He later takes Maja's place as the second High Krawl with authority. He is an obese, pot-bellied green creature with red eyes, sharp teeth, and thick arms. He is rather spherical in shape, his body mainly consisting of his massive belly. His stomach appears to have a green portal on it. In battle, his stomach bloats up immensely, now forming his entire body. He wants to eat the whole Nanairo System and the rest of the systems, though he already succeeded in eating Aldous's home planet Giorna. Rallen does stop Gronos on Aoboshi or Akaboshi, which ever one you picked second. The property of Gronos is Aurora, so get some Corona Type Spectrobes to fight him. Like every High Krawl, he has a battle form when you fight him.
- He bounces around and sends a shockwave that knocks you back.
- He opens up and shoots a laser.
- He spins and rams into you.
- His most deadly attack: He opens up and a portal into his stomach appears. He sucks you in and does a lot a damage.