Reborn As A Portrait

While others transmigrate into characters to follow the plot, he ended up as part of the background... Could there be a more tragic life? Maybe now isn’t the time to dwell on that. He should first master *How to Become a Qualified Painting* so as not to be disposed of as a dangerous object by caretaker Filch or someone else. But the bigger issue is that magical portraits are alive—and he has no idea whose portrait this is. Long black hair, green eyes—who hung a mirror opposite his portrait? Absolutely necessary, infinitely grateful—on the ancient yet vividly colored canvas, a youth in an ornate cloak smiles at his reflection. Above the frame are three curling Ancient Greek letters, while below are eight even more elaborate ones~~ Only in the far-right corner of the canvas are two elegantly slanted English letters: S.S Well, after a glance at the lace-trimmed cuffs, at least one thing is certain—he is definitely not that Potions Professor, who would never tolerate a portrait of himself wearing such attire. So... who is he, then?