Soul Calibur

The Soul Calibur (ソウルキャリバー), known as the spirit sword (精神の剣) is one of the titular weapons of the Soulcalibur series along with Soul Edge.

Overview
In both timelines of the Soulcalibur universe, Soul Calibur was created by the Hero King, Algol, the original wielder of Soul Edge after losing his son to the cursed sword. Algol vowed to create a holy sword from the purified shards of Soul Edge that would oppose the evil sword, being its equal in strength and opposite in intent. Algol enlisted the help of the greatest sage in the land, who used purified fragments of the cursed sword to forge a new spirit sword, to be known as "Soul Calibur". After many failed attempts, the holy sword was born when Algol sacrificed himself to complete the ritual. However, the sword that was created was far from good due to Algol's thirst for power, and it was extremely similar in nature to Soul Edge. Nonetheless, the tribe that was tasked with guarding the sword slowly purified it to the point that it could be considered a holy weapon, while keeping dormant the dark soul that rested within the sword. The guardians lived in seclusion, passing the sword from generation to generation in secret. Whenever a warrior vowed to take on Soul Edge on his own, Soul Calibur appeared to prevent the cursed sword from causing any more damage. When wielded by King Arthur it was referred to as Excalibur. Soul Calibur finally appeared, somehow transformed into a different shape, as one of the Ling-Sheng Su Temple treasures, a sword called Krita-Yuga. The other treasures, Kali-Yuga and Dvapara-Yuga, are linked to the holy sword. Kali-Yuga, a holy staff, is capable of absorbing different energies in order to strengthen Soul Calibur. Dvapara-Yuga, the holy mirror of the Ling-Sheng Su Temple, is used to help keep the purity of Soul Calibur intact and has the power of purifying the corruption of Soul Edge. However Soul Calibur is becoming manipulative like her brother weapon Soul Edge, for her purpose to bring order in a ruthless way.

It was first mentioned during Zasalamel's records. Later, when overhears about the spirit sword, he plans to seek after Soul Calibur in hopes of defeating. However, Taki prevents him from doing so knowing that the spirit sword is also revealed to be a corrupting influence just like Soul Edge. Geiz later decided to forego his quest to find Soul Calibur after the ordeal against Chai Xianghua, Krita-Yuga's wielder.

After becoming aware of, Taki decides to search for the spirit sword as a contingency in the event becomes Oma Zi-O.

Like Soul Edge, Soul Calibur's power rivals that of Oma Zi-O.