Zegion

Zegion (ゼギオン) was originally an injured insect that Rimuru found in the Great Jura Forest, tasked with guarding the Treants' settlement upon being taken in. Zegion was later appointed as the Guardian Overseer of the Ten Dungeon Marvels, and also received the title of "Lord" as one of Rimuru's Twelve Guardian Lords. He is also one of Rimuru's three strongest, along with Benimaru and Diablo.

Original
During his debut, Zegion appeared to be an extremely large beetle with characteristics of both stag beetles and rhinoceros beetles.

Humanoid
Later he evolved into a humanoid form that looks like a warrior clad in pitch-black exoskeleton with visible golden joints. A red-tipped, sword-like horn protrudes from his forehead. The exoskeleton took the form of Rimuru's preference. After undergoing Rimuru’s Harvest Festival ritual the Magisteel given to him by Rimuru that had previously evolved into Adamantite has evolved into Scarletite.

Personality
Zegion usually has a calm and serious demeanor, speaking very few words. However, he is fiercely loyal to Rimuru and any words he interpreted as an insult to Rimuru would quickly anger him. Zegion has a soft spot for Apito viewing her as a sister and would always put favor on her. Due to being saved by Rimuru in the past, Zegion sees him as a god who is makes plans ahead of time and is always humble in his presence. To repay this kindness, he strives to be a prove his worth to Rimuru and won't hesitate in getting stronger despite being already strong.

Background
Zegion was born in the the otherworld alongside Apito to fill in the remaining vacant spots in the Twelve Insect Generals. However, Zess, wary of their potential, eventually attacked them, forcing the pair to flee to the Central World.

When they arrived, the pair were immediately attacked by a Blade Tiger. Zegion fought and defeated the blade tiger but was heavily injured. Fortunately, they were found by Rimuru who was impressed by the small insect's display of strength. Sensing Rimuru coming to him and Apito, he attacked Rimuru recklessly, to serve as bait and allow Apito to flee, only to be stopped by Apito herself when she asked for Rimuru's protection due to her recognizing Rimuru's strength and his intention to help them. Rimuru agreed in exchange for Apito providing him some honey. Due to their injuries, Rimuru patched them up with his own slime body to aid the healing process and replaced their missing exoskeleton parts with processed magisteel. He was named and tasked to guard the treants' settlement.

Trivia

 * In a running gag Zegion and Apito met Milim Nava, she gave them such a fright that this motivated the two in getting stronger.
 * Alongside Benimaru and Diablo, Zegion is one of Rimuru strongest subordinates.
 * Zegion is a disciple of Veldora having been train in his Veldora Style Killing Arts
 * Zegion is a disciple of Veldora having been train in his Veldora Style Killing Arts