I feel like 40k deserves it's own alignment system. On one axis, Discipline/Stability/Anarchy, on another, Naivety/Pragmatism/Cruelty, and on the last, Loyalty/Unpredictable/Ambition. With Neutrals for all three, of course.
Eldar might be Disciplined, Loyally Pragmatic xenos, while the Orks might be Anarchical, Unpredictably Cruel xenos.
...and while I might be a fanbot, sometimes I have to embrace my inner Space Marine.
Never falter, never fail.
That is a fallacy, an untenable command.
We will all fall one day.
Where you fall, the entirety of the Imperium rises to support you, and direct your aim once more to the Emperor's foes, even unto their dying breath. They shall not let you down, and neither shall you let they.
We all stumble sometimes.
When you stumble, your brothers are there to provide covering fire, as you are there to provide for when they inevitably stumble. Only the Emperor is without flaw; rely on your brothers to deflect the enemy from yours.
We must fight continuously.
Why you fight, only the Emperor and you can decide, in your hearts. But let it be for the whole of humanity, and the hope of another day spent beloved by the Emperor, and your fellow man.
We can never stray.
Should you stray, you betray humanity, and threaten the sanctity of thousands of worlds, billions of lives. Your former brothers must take up arms against you, and their anguish will fall like the Emperor's own wrath. Our most divine Emperor shall turn away from you, and you will be bereft of his light. All that will be left to you is your wretched self. No man can stand against the tide of xenos and chaos on their own, even the greatest among them. Stand instead before your fellows, beside your brothers, under the Emperor, and atop the corpses of the martyrs who came before, and face our Foe in this never-ending struggle, and find purpose in war.