Simon Apkumra had lived all his life on Alpha Lexar in the Ystryd Sector. A planet well off the main imperium trading routes, but self supporting, most of the inhabitants had seen no need to leave it's graceful pastures. At least until the filth of the tyrannid hoard invaded their lives.
On successfully completing his educational obulous at the imperial college in the citadel,as laid down by the imperial ecclesiasti, Simon had spent most of his life in the green hills watching over his flock of Samra - a native type of camel farmed for it's meat. Simon spent most of his time meditating on the ways of the universe. The hills were not really such a deep green;on Lexar everything appeared green due to the small green sun which also provided the planet with its heavy gravity - twice that of Terra. Accordingly everything on this planet was massive, even the native equivalent of daisies were miniature trees.
Within days the tyrannid horde had descended like locusts and begun to lay waste to the planet. Within a week they had overrun half the planet and wiped out the white knights to a man. In this time Simon had sought out the protection of the citadel. It was not just his reluctance to leave his flock to be bio-degraded by these insiduous aliens that had led him to drive his flock of Samra before him. Knowing that the populace would need the extra provisions and true to his philosophy on life, he preferred that his flock die for a purpose rather than simply be chemically desintegrated. The planetry militia had up until this point been relatively passive. Afterall they were not space marines and had been forced to take a background role, performing mainly policing work, organising public shelter, resource control and taking care of funeral ceremonies for the dead. Of the last, the gathering together of the remains of the white knights and their honourable disposal was one of the more favourable duties.
On the 10th. day when all had given up hope of salvation, Simon, after having prayed through the night, appeared in the grey twilight of dawn resplendent in a polished armour of green. He'd taken all night to prepare and polish the armour of the last white knight so that it glistened in the green sunlight. Layed out before him, the armour of the other 999 white knights who had laid down their lives for the planet. He looked to the gathered populace with their heads layed low in expectation of a miracle. Holding a pitch torch high he paced through the crowd, picking out here and there a face that only he seemed to recognise. When he was finished he returned to his place lighting up the armour of the fallen space marines with his torch."Of you who die with me today, who will carry the torch when I fall?" "I" was the universal answer. "Then take up your armour and prove your worth!" Simon spoke on "It is an honour to die with you today .The last man standing must return to pass on the torch". He turned to the crowd "Who will carry the the torch when we fall?" "I" came the answer from every man, women and child who had not been chosen.
That was the last the populace of the citadel saw of them. All day the sound of battle and alien screams were heard within the citadel. Finally as the daylight dwindled a solitary figure appeared amidst the battle smog holding the torch of Simon high. As daylight broke on the second day, a single figure stood before the crowds, walked among it's ranks and called on 999 to follow the torch. Again the question was repeated. "who will carry the torch when I fall?" "I" came the answer from 999 voices in unison. "And who will carry the torch when we fall?" "I" answered the crowd as one man.
So the battle continued. Each night the populace would search the battlescape gathering up the remains of the dead, collecting their armour and weapons together to be polished and armed for the next day. Thirty days and Thirty nights had passed before the imperial fleet finally appeared. The inquisition found it hard to believe that the white knights had been wiped out to a man and that the natives had held out for so long, but finally convinced of the facts and in no position to debate them, immediately permitted the planet the right to its own space marine chapter. A chapter however that refused any genetic intervention from the imperium.
Of course it took centuries to purge the planet of the tyrannid infection; Simon became a legend - a saint, but with the support of the imperium the outcome was already a foregone conclusion. The planet became a training ground for the green knights, as they came to be known, who swore that no human would ever suffer again under the tyrannid horde. Finally the only surviving tyrannid nest on a small island was reserved as a training ground for "St. Simon's Templars" as they officially came to be known. After having brought their own planet again under imperial control, the 'saints' now carry their cleansing torch to other infested planets and have led several crusades against the tyrannid infection all over the galaxy, becoming so successful that they were knicknamed the "Green Crusaders"or the "Saints".
No enemy has succeded in dowsing the flame of life which they always carry into battle with them.
To date the 'saints' are the only space marine chapter that are not genetically engineered and still remain successful in the fight against the tyrannid horde. They are also officially allowed two chapter colours. On their home planet in honour of the white knights who layed down their lives, their armour is still white with a metallic green piping. Off planet their armour is a light metallic green, a reflection of how their white armour appears under their home planet's sun.The chapter also has its own suicide squad, a group of kamikaze veterans led by their own priest who vow to lay down their lives rather than retreat under enemy pressure, just as the original thousand did. This squad always looks for the toughest jobs going and have black armour, the colour of the death that they seek and deal out.
Occasionally when the reserves have been called up in support, their white amour has been seen in other sections of the galaxy. These occasions are rare as there is always a constant flow of new recruits from the home populace. It never takes very long to replenish the ranks.
Their proven weapons, flamer and toxic thrower, added to their supernatural strength and natural instinct in seeking out and roasting tyrannid nests before they hatch out, remain the only effective cure against the tyrannid infection.