cross_calibur_(fate)
Mysterious Heroine X Alter (Fate)'s weapon. It is often seen resembling a red double bladed lightsaber, but originally took a form resembling a glowing red energy sword variant of Himitsucalibur (Fate) and by extension Excalibur (fate/stay night) with red markings on its hilt. It can also transform into a chainsaw.
Similarly to Himitsucalibur (fate), if its portrayed in its original form without the glowing element, it may simply be tagged as Excalibur (fate/stay night).