Talk:Natsuki Subaru/@comment-120.158.14.202-20200921173147/@comment-43404528-20200924001704

[SPOILER ALERT FOR THE WEB NOVEL BE WARNED: ARC 6 SPOILERS]

While it isn't definitively confirmed, what we've seen makes me believe that a sage/a sage candidate is a person who can wield every authority of sin. [LAST CHANCE TO TURN BACK] When Subaru and the gang were at the Pleiades Watchtower, he came across gates in a hidden underground section. When he walked up to each gate, he was only allowed to open three (which corresponds to the number of Authorities that he had at the time, though at this point it is unknown if this confirms Return by Death to be an authority as he was only confirmed to have the Authorities of Greed and Sloth). Additionally, when Rui splits herself and inhabits Subaru's body as the Authority of Gluttony, he was able to open an additional one of these gates in the Light Novel.

With the knowledge that Flugel is definitely connected to the authorities (he gave Petelgeuse the box containing the Authority of Sloth), this all leads up to the conclusion that sages are people who wield/can wield every authority without entirely losing their mind (though Subaru still experiences major pain when using the Authority of Sloth probably because of how diligent he is while he doesn't experience any pain when using the Authority of Greed probably because of his selfish/greedy intent to save everyone no matter the cost).