User blog comment:B214/High School DxD EX/@comment-4547267-20150903042049/@comment-4547267-20150903145423

According to Kurenai, Ix' crimson sword, "Scarlet Blade", is a Galatine III. Just like Durandal IV, it is a development type of the legendary sword Galatine that is purely dedicated for Ix.

Galatine is a legendary weapon that is considered as the brother sword of Excalibur. It is said to never have its edge nicked. If it is a sword dedicated to Ix and is a development type, then the sword would be safe even if it is covered with Ix' Power of Destruction. They chose the robust Galatine and created a new model from it.