The Hydra cloth is based on the Greek mythological monster, Hydra. But due to its minor power it currently only has one head. Yet it is Ichi's main and only know form of attack and defense.
According to him, poisonous claws come from every part of his cloth: the target hit by them becomes paralyzed and slowly dies.
Once they hit the target, the claws come out of the cloth, but new claws grow very fast, giving an infinite supply - exactly as the mythological monster, who if any of the heads were removed, two would grow in its place.
The Anime version differs slightly from the manga original, were as a pelvis armor and leg armor has been added.
Ichi is one of the 100 orphans that were brought into Graude Foundation to fulfill a project—to be trained into becoming future saints for the goddess Athena. Only 10 of the children survived the entire process, and they grew up to become bronze saints.
In the original manga, it is was revealed that all 100 orphans were actually half brothers, with their father being Mitsumasa Kido, the man they have grown to despise for tearing them from their happy homes.
After some time living and training at the orphanage, the orphans were selected to different places all over the world and sent by Mitsumasa Kido to train and bring back the saint cloth in order to protect his foster granddaughter, Saori.