To make a blade strong enough to cut down monstrous beings, one must either have mastered the basics of sword essence, or possess a ridiculously well-crafted weapon to do all the work.
Judas' manifestation had neither of those qualities. Judas didn't know how to wield sword essence, and his manifestation wasn't crafted to be strong.
The golden aura covering the blade was merely excess essence being emitted. Of course, it would be deadly to anyone who dared touch it due to its unique properties. But to Ferris, a master swordsman by this point, he had to be critical of what kind of weapon he was holding.
Ferris held the sword's essence by the reins and began resonating with it.
Just like how he normally handled sword essence, he first shaped it to fit the sword's proportions, then sharpened it, then tempered the already sharp essence swirling around it, then shaped it further toward perfection, then sharpened it again.
Shaping, tempering, sharpening.
