There are defensive auras as well as offensive ones.
"Increased strength from the Strength Aura, the Holy Fire Aura that causes periodic damage around it, I haven't seen anyone use this one before. Oh, it's too difficult to learn, only Gerry could master it."
"There's also the Spiny Aura that reflects damage in melee, the Aiming Aura that increases accuracy, the Focus Aura that provides concentration, the Ice Aura that slows enemies down. I haven't seen this one either. Oh, it's also too hard to learn, but if they didn't master it, how did it get recorded here? It can't just be speculation."
"There's the Frenzy Aura that provides a berserk effect, the Defense Aura that reduces enemy defenses and resistances. Haven't seen these either, I guess no one has learned them..."
"If you think about it carefully, there are a lot of offensive auras that are missing, and many are different from what I remember."