User blog comment:B214/Question and Answers/@comment-222.222.236.170-20131207063914/@comment-16281343-20131207064819

Sacred Gears can be grouped as normal, rare, and the Longinuses.

I don't know where Blade Blacksmith is grouped there but what it can be said is that the more powerful a Sacred Gear is, the lesser its number is.

Normal Twice Criticial is considered a normal SG, since it just doubles the power of the user.

Twilight Healing is considered rare, since it heals any being.

And of course the Longinuses, which is a congregation of the abilities of multiple Sacred Gears and has the ability to kill Gods.