During the Isu Era, Hephaistos was known as "the maker" among his people, having invented many Pieces of Eden and at one point trained Consus, who later used his teachings to develop his own Pieces of Eden, such as the healing devices known as the Shrouds. During his time in Atlantis, Hephaistos also constructed a forge beneath Poseidon's palace and created numerous weapon blueprints which could be used with it.
Likewise, he was the engineer responsible for the Ancient Forge on the island of Andros and the smith behind the the Spear of Leonidas, which could be upgraded at this forge. The Forge held the apparent mold for the spear, as well as the molds for a sword, a battleaxe, and a halberd. The Hammer of Hephaistos wielded by the Cyclops Arges was allegedly another one of his creations. 
In Greek mythology, Hephaistos was said to have a limp, and when this was discovered by the goddess Hera, who was said to have been his mother, she threw him off Mount Olympos. Hephaistos landed in the sea near Lemnos, where sea deities rescued him.
Hephaistos also helped the hero Herakles with at least one of his tasks, albeit indirectly, as he was the creator of the rattle which the goddess Athena gave to Herakles to scare the Stymphalian birds out of hiding.
Influence and legacy
Many of Hephaistos' creations survived the end of the Isu's reign, becoming objects of divine origin among humanity. During the 5th century BCE, the islands of Thasos and Lemnos were known as the Hephaistos Islands, with the latter housing a notable temple dedicated to Hephaistos. The volcanic island north of Argolis was called the Foundry of Hephaistos.In addition, the polis Athens housed a temple dedicated to him. Some claimed that a cave hiding curious architecture in its depths in the northern parts of Malis held Hephaistos' workshop.
Also during this time, Kassandra made her living as a mercenary. Due to her nature as a hybrid with high concentrations of Isu DNA, she had access to a range of powers within the Spear of Leonidas, one of which included the ability to temporarily imbue her weapons with the divine flames of Hephaistos' forge.
Behind the scenes
- Assassin's Creed: Syndicate (mentioned in Database entry only)
- Assassin's Creed: Odyssey (statue only)
- Discovery Tour: Ancient Greece
- Assassin's Creed: Rebellion (mentioned only)
- Assassin's Creed: Syndicate – Database: Reconstructed Data 003
- Assassin's Creed: Odyssey – The Fate of Atlantis: Judgment of Atlantis
- Assassin's Creed: Odyssey
- Assassin's Creed: Odyssey – Historical Locations: Lemnos: Temple of Hephaistos
- Discovery Tour: Ancient Greece – Arkadia: The Stymphalian Birds
- Assassin's Creed: Origins
- Assassin's Creed: Brotherhood
- Assassin's Creed III