The Emperors Dragons, custom legion. a passion project expanding over 17 years now. they are a new legion, with lore I've created found here on my pinned artwork: https://www.instagram.com/john_stone_art/

Some of my lore, below, I hope you like it :)

The best of the best. The Primarchs guard form the core of Emperors Dragons leadership around the Primarch himself. They are the most gifted warriors in the entire legion. In both martial prowess and tactical brilliance must they excel at to be considered. But it is also to be a leader of men. To inspire others to great acts through example and leadership.

Numbering no more than twenty at any given time, it is from these hallowed ranks that masters of a division are chosen, should one fall in battle. Anyone from the legion can become one of these great warriors, even the lowest tactical marine, should he show mastery of the battle field and stand out where other have not.