Explanation of God’s Right Seat and the Archangel Attribute

Terra of the Left is blessed with the "God's Medicine" attribute, as he is aligned with the Archangel Raphael after purifying his body of the Original Sin. As a result of his alignment with Raphael, he is associated with the color green and the earth. He wears green ceremonial clothing and holds the position of the "left" as his name indicates.

To be blunt I really don’t care about the loss of a single spiritual item. After all, we are far removed from normal magicians. We cannot use anything not specifically modified for our use. What value is there for me in a tool that someone Raphael-aligned like myself can’t use?
(Toaru Majutsu no Index Volume 13, pg 224)

“You’re saying there’s a method to eliminating original sin other than through faith in the Son of God?” “Through a spell that could be considered cheating, yes. I have heard that God’s Right Seat has succeeded in diluting their sin as much as possible, but they have not managed to eliminate it altogether.” Lidvia was bound to her seat, but she spoke as calmly as if she was in complete control. “But because they have incompletely eliminated their sin, they can carry out spells of a level surpassing what normal people can. It is said that they can even use the normally unusable spells that deal with the angels and the Lord.” “...Well, I suppose eliminating original sin really is the final goal of humanity. And if you could manage it, your ‘quality’ as a human would approach that of an angel. But...” “Yes. ‘Sin’ in this case also means the fruit from the Tree of Knowledge. If you lose that, you also lose the ability to be a normal magician and use the magic that is for humans to use.”
(Toaru Majutsu no Index Volume 14, pg 66)

Kamijou was finally able to focus on all of the attacker at once. It was a man wearing green ceremonial clothes. He was wearing green from head to toe. He was a bit short for a white person as he was about Kamijou’s height or maybe a little shorter. On the other hand, he looked about twice Kamijou’s age. He was quite skinny so his ceremonial clothes were very loose fitting. His sunken cheeks gave him an odd sense of vitality. Kamijou held out his right hand and asked the ceremonially-dressed attacker a question. “...Are you from the Roman Catholic Church?” “I am, but I would prefer it if you said I was from God’s Right Seat.”
(Toaru Majutsu no Index Volume 14, pg 116)