(A bit late to reply, I forgot to post, but hopefully this will still be canonised)

Abelhard Rote, the Lord Inquisitor was the one who ordered the bells be rang, yelling for his men to rally as he spotted the  flames turn as he returned from patrol.

He saw the artefacts be used. He fought alongside his brothers in faith, saw magic beasts bring ruin to districts of the Imperial City, and felt small. Though he joined the chants and prayers of his Brothers in the Synod, while fending off foes with his warhammer, he couldn't be sure if his efforts even contributed.

That night, after tucking his children to bed, and ensuring his wife was firmly asleep, Abelhard crept downstairs and prayed before his shrine to the Spirit.

"Your Holiness," he began, "You have shown us such strength today that I am even more enamoured by your glory. And though, I am sure my recital of the scripture, as my Brothers did, contributed in some way to the direction of your Divine Justice, I have to beg. Imperial Spirit, I beg to be used as a tool for you and your flock, a weapon of the faithful and a man indomitable to the heresies I face every day. I shall give my bodies over to your scriptures, as a symbol of my allegiance to your hallowed words. Imperial Spirit, I beg for the power to see the Great Way achieved: to contribute in my own way." He paused for a moment, his breath shaky, "Neben Mir." He said finally, going to slip back to bed.