Not Swords But…
In a large room of an inn, Jacob was closely examining the twin swords, but there was nothing extraordinary about them. He even tried all types of mana, spirit, and aura; he even dripped his blood on them, but these swords are just like any typical epic sword.
To measure a magic weapon's rank was very easy and depended on two factors.
First, mana channeling; one just needed to see how much magic power a weapon can channel without bursting. Every time someone goes through a rank evolution, their mana would also go through a qualitative change.
A rare magic weapon can only handle rare quality mana, while some weapons made with extremely resilient materials can endure a bit higher level of mana.
Although these twin swords were only epic rank, they could still channel mana, spirit, and even aura, which made them, indeed, somewhat extraordinary.