Showing my view of the Shadowbolts.
From left to right:
Descent, Eclipse (the only name I made, as the second stallion didn't get a name) and Nightingale.
And here, some headcanon:
The Shadowbolts originally weren't real living ponies, just simple entities created from magic by Nightmare Moon, to corrupt the Element of Loyalty. But when Luna was set free by the Elements of Harmony, the Shadowbolts were cut of and came to real life. Since then they live in the Everfree Forest and planing how to take revange for their mistress' "murder". Also, it's a small thing, but as originally they weren't real things, they don't have cutie marks.
Characters and MLP:FiM (c) Lauren Faust, Hasbro
Artwork (c) me
No stealing. Thank you.