Hermod (The Silver Scribe)

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An alternate version of Mercury, based on norse mythology and on other messenger gods, as well as Mercury's normal personality.

The silver in the title, as well as the alchemical silver cutie mark are references to the original bands of the element mercury, quick silver.
The tear drop tattoo and the leather bracelet are references to Viking lore: leather being a material used in Viking jewellery and the tattoo being a reference to the legend of the death of Baldr.
The symbols around him represent the other inner planets and the two nearest gass giants.
The rainbow colour of quill is a reference to the rainbow messenger goddess of Greece, Iris.
The quill itself is a little harder to explained: I see Mercury as a sort of hobbiest writer and the same goes for Hermod but the quill actually has more to do with this version of him being forgetful and needing to wright things down a lot, to avoid distorting his messages.