Angel became a trademark in the potion industry easily, due to all the potions it released. All of them were high grade potions which showed miraculous effects on everyone. No matter their race or origin.
With the growing reputation of the company, Rio, who was the sole owner of it, also became famous.
When he joined the academy and the world learned of his academic achievements and talent, they were all spread to every corner too.
It didn't take long for the term 'Angel' which was just symbolic to a potion business company, to be attached with his own image.
The Devil who was destined to die, became known as their Angel.
That is what Rio wanted.
How dangerous the effect of the public belief, and normal image in the eyes of commoners could be, Rio knew all too well.
