Soul Embrace as featured in Soulcalibur III.
The Soul Embrace later appears as the Embrace of Souls in Soulcalibur IV as Kilik's strongest weapon, although they do not resemble the Soul Embrace excepting the fact that they seem to be made up of the two soul swords. In Soulcalibur: Broken Destiny, a more powerful version of the Soul Embrace under the name Broken Destiny appears, appearing as a fusion of the two blades in their Soulcalibur IV designs, and is unlocked for Siegfried by completing the Gauntlet mode, and is also unlockable for Nightmare.
This canonically took place after Siegfried pierced Soul Edge with Soul Calibur, and Siegfried carries them with him throughout his story in Soulcalibur III. The Embrace was broken when Siegfried and Nightmare clashed in the Lost Cathedral. They aren't a usable weapon in Soulcalibur III.