Acheron

From the Soulcalibur Wiki

A long sword once wielded by Cervantes. It probably originates from Cervantes' pirate days. He left it, alongside Nirvana, since their power paled in comparison to Soul Edge, but recovered both weapons from his flagship, the Adrian, once he lost the wicked sword. He discarded it once again after creating the new Female Soul Edge. Acheron has a sturdy design and is good for both offense and defense. In Soulcalibur IV, since his own Soul Edge had reintegrated back into the main Soul Edge, Cervantes wields Acheron once again.