This fic describes Uriel's feelings for Katou from the moment he was slashed in Vol 16 to his death in the manga at the end of Vol 18.
At the Cross: Stabat Mater Dolorosa:
At The Cross Her Station Keeping
Stood the Mournful Mother Weeping
Close to her son at the last...
I saw you lying in the pool of blood when I crashed in with the tankers. I have predicted this, I gave consent to your wish to join to the Messiah's fight, and I know you will come to this brutal end....I sent you to your Way of the Cross...
Through her heart, his sorrow sharing
all His bitter anguish bearing
now at length the sword has passed...
You laid on your sickbed in desolation, in the shade of death, you took the slash that was supposed to for the Messiah, the Messiah was distraught. I am not the type that could shower you with an extravagent show of affection, I did not laugh with you like the Messiah, I did not squeeze you, give you fives, I seemed resigned and impassive, watching from a distance, but Yue-kun, do you know i felt as sad as the Messiah? I could recognize you in whatever face to make for yourself, when the Messiah was just as confused as you were, having lost your memory. I do not just resurrect you for the sake of the Messiah, I resurrect you entirely for your wish, for I saw how you hated to die as an anonymous junkie, thus I carried out your wish...I made you the puppet to house your soul, I said yes to your incarnation and it was i who did it, I caused all your suffering. How will it not torment me inside?
O how sad and sore distressed
was that Mother, highly blest,
of the sole-begotten One...
Though you confided in me, all you will live for are Messiah and your Kira Senpai and above all, yourself, let it be, I do not have another set of vocal cords to crush, I do not want to commit the same mistake as I had to Alexiel. You were eager for matyrdom and rush to all kinds of danger, though you have not thought that if you die, I will mourn for you like Mary over Jesus. I will mourn more than anyone else, even I do not necessarily show it. But let it be according to your word.
He above in torment hangs,
she beneath beholds the pangs
of her dying Son...
All I wanted is to comfort you and to be a shoulder to cry on when you were in so much pain. I have remained with you, you leaned on me as you wanted during your ordeal. The Via Dolorosa is all over. The Gates that closed on you were the rocks that sealed your sepulchure, I have to give you up as the Gates were closing. Farewell, my glorious son. The Via Dolorosa is only a herald to the Via Lucis.