'It is said that any brother of the Crimson Shrikes Astartes chosen to be elevated to the elite of the First Company must undertake a series of trials to prove they are worthy, the most notorious of which is known as 'The Piercing'. The megafauna of the Shrikes' homeworld is covered in barbs as long as a man's arm, and covered in the most virulent toxins. The chosen is taken to a suitable tree, and subjects himself to having these thorns pushed through his body. He is then left to hang for nine days and nine nights, a sacrifice of himself to the Emperor. The toxins wash through his blood, causing hallucinations and visions to fill the Astartes' mind. Not all Marines survive this torment, and those that do are said to have some foresight of future events granted unto them, including the manner of their death. Whatever the truth, the warriors of the First Company, also known as the 'Thorn Wreath', are brooding, Introspective souls. They let the screams of the heretic and the crash of the Bolter speak for them'
'Rituals of the Raven Guard and Successors' - Tominas Rotajz
Below can be seen Demi-Squad Yestine of the First, led by Jor Yestine. These brothers were a fearsome force during the initial phases of the War, and Jor was the obvious choice to lead 'Hunter Revealed' after the mortal wounding of Captain Shraane. Indeed, after the War's conclusion, Brother Yestine's command capabilities and consistent tactical excellence even against the forces of the Emperor's Children Traitor Legion led to his promotion to Captain of the Ninth Company.