|Sword of Actuation|
Yobimizu no Tsurugi
The Sword of Actuation is the Skull Knight's trump card for fighting major enemies or dealing with dire situations, created when he augments his sword with the molten mass of countless Behelits he had previously swallowed and stored in his body.
The sword is essentially the Skull Knight's Sword of Thorns, only its size is increased and its blade covered with the molten remains of the countless behelits that the Skull Knight ingested. The result is the large blade being crimson-colored with multiple facial features.
The full extent of the Sword of Actuation's power remains unclear, but the Behelits give it the ability to manipulate space-time like the God Hand. As seen, the Skull Knight used his sword to rip portals across different dimensions.
Forced to reveal his weapon while saving Guts from Slan, the Skull Knight stated that he intended to use the Sword of Actuation to fight the God Hand. But the event appeared to reach Griffith's notice, biding his time for the Skull Knight to make an attempt on his life during his final battle with Ganishka. Once the Skull Knight appears, Griffith uses his powers to redirect the blade's attack to Ganishka, causing the World Transformation to occur.
It is theorized that the Skull Knight created this weapon in order to cancel out Void's ability to bend space, although this remains unconfirmed.