|Weapon: Seiryu Spear|
|Blood Type: O|
|Occupation: Executive of the Gerard Foundation|
|Family: Puella Marionette (foster daughter)|
|Appears in: Toshinden 4|
Eos is a fictional, playable character in the Battle Arena Toshinden video game series. She made her first and only appearance in Battle Arena Toshinden 4, as one of the unlockable sub-bosses.
The angel-like Eos is a biotechnologically-produced masterpiece of the Gerard Foundation. An incredibly powerful warrior, she can predict every move of her opponents, thus making her unmatched at fighting. However, her strange powers alarmed the members of the original Gerard Foundation, including the Shitennou (Chaos, Cupido, Gaia, Uranus) and even Master.
Eventually, Master and Uranus sealed off Eos' power to keep her from disrupting their own plans. Years later, however, she was found by Eiji Shinjo, who had become the new Master of the Gerard Foundation. Requesting that she release her powers to help him in his fight against an unknown evil, she managed to break Uranus' seal and pledged loyalty to Eiji as her new master.
From there, Eiji had given her the Seiryu Spear, Mondo's old weapon, which was one of the powerful Four Sacred Arms. As soon as she held the spear, it changed its shape into a beautiful jeweled rod. She then joined Eiji's team as one of the executives of the Gerard Foundation, planning to vanquish the approaching evil and return both order and peace to the world.