Seryu receives Koro when she became an imperial police. She is often seen with Koro since then. During the battle between Mine and Seryu, Koro suffered large amount of damage and was eventual bifurcated with Mine's Pumpkin, which made it unable to regenerate. Seryu then used a suicide bomb as her last resort in an attempt to kill Mine, taking out the entire valley, along with herself and Hekatonkheires.
Hekatonkheires, named as Koro for short by its last owner, was a biological Teigu resembling a small white dog that stands on its back legs. When ordered, it had the ability to grow to a much larger size, increasing its strength and durability. It ferociously attacked enemies by devouring them. Koro could also grow large muscular arms and furiously unleash a volley of punches. Like other biological Teigu, it was able to regenerate if damaged, unless its core was destroyed. The aforementioned core was an orb in its head.
Later on, with the help of Dr. Stylish's Perfector, both Seryu and Koro's bodies were modified to use a group of highly advanced weapons branded The Judgement of the Ten Heavenly Kings (|十王の裁き, Jūō no Sabaki). These weapons were stored within Koro's body.
- Number 1: Shinkou's Ball of Justice (正義秦広球, Seigi Shinkō-kyū): A large flail that can take down a large number of opponents.
- Number 2: Four missile turrets that can be used to send out a volley of missiles.
- Number 3: A large sword with a giant blade. It can execute enemies.
- Number 4: A hookshot
- Number 5: Enma's Spear of Justice (正義閻魔槍, Seigi Enma-sō): A large drill that is capable of mowing down a large number of opponents. It can be launched to be used as a long-range attack. The drill can also explode if necessary.
- Number 6: A giant armor-reinforced missile that explodes.
- Number 7: Taizan's Cannon of Justice (正義泰山砲, Seigi Taizan-hō): A long ranged anti-tank rifle with great destructive power.
- Number 8: An arm with an unknown ability. It was used during her Justice Volley Fire.
- Number 9: Justice City Detector (正義都市探知機, Seigi Toshi-tanchiki): An arm with a radar that detects living beings in a certain area.
- Final Number: Chakravartin Furnace of Five Hells (五道転輪炉, Godō Tenrin-ro): A last resort in the event of her defeat she has an explosive device implanted in her head. The explosion triggered by this suicide attack was easily enough to fill the small valley in which she and Mine had fought their final battle. The destructive power it possesses was proportionately intense, laying waste to the surrounding environment.
- Berserker (戦鬼, Senki): The trump card of Hekatonkheires which would evolve the Teigu into a more bestial form enhancing its physical abilities. In this form, its roar was powerful enough to stun opponents alone. According to Seryu, after using Berserker, Koro would overheat and be unusable for a few days. That statement was proven to be an exaggeration, since Seryu was capable of using it again directly after using Berserker.
- In Greek mythology, the Hekatonkheires, meaning "hundred-handed ones", were three giants.
- Berserkers were Norse warriors said to have fought in a wild, trance-like fury. This characteristic later gave rise to the English word "berserk".
- His nickname, Koro, could refer to the Japanese word "Koroshiya", which means "professional killer".
- Hekatonkheires apparently consumes a large quantity of food regularly. Its food can be anything provided that it is meat, as it devours the bodies of both Sheele and Chelsea as well as some death row prisoners.
|Members:||Run · Wave · Kurome|
|Deceased:||Bols · Run · Seryu Ubiquitous · Dr. Stylish|
|Teigu:||Demon's Extract · Grand Chariot · Mastema · Yatsufusa|
|Lost Teigu:||Hekatonkheires · Perfector · Rubicante|
|Puppets:||Apeman · Desta-Ghoul · Doya · Henter · Kaiser Frog · Natala · Rokugoh · Run · Wall|