I singled out Cathedral as my favorite character from Alex Ross and Mark Waid's 1996 Kingdom Come series, mentioning that as far as I knew he appeared only in a single, two-panel scene in the first issue (fighting The Whiz, only to be tossed aside by Wonder Woman) and on the cover of the first issue (along with 32 other characters). The key to that cover in one of the trades is where I learned the character's name, as he goes without one in the comic itself, and found a simple five-word description of the character: "Holy terror of the underworld."
I was recently re-reading–well, skimming–Kingdom Come in the form of a well-loved/falling apart library copy of Absolute Kingdom Come. I paid more attention to the copious supplementary material than the story itself, which I've read and re-read so many times before, although I did scan all of the pages for little details, particularly all of the pages with crowd scenes, as the pages in the Absolute version are so large that it's much easier to see background characters.
I learned a little more about Cathedral in this volume. First, there's the above sketch; he appeared with Catwoman II and Manotaur in the section of the sketch gallery marked "The New Breed." Here we get more than five words on Cathedral. Writes Ross, "Instead of dark-clad, cloaked figures romaing around on building rooftops and edifices, I threw together someone who would blend in better."
Sheesh. Look at the detail on the sketch. No wonder Cathedral was relegated to just two panels, which only showed parts of him anyway. He looks like a real pain in the ass to draw; can you imagine him starring in a monthly comic? It's hard to imagine anyone drawing that guy on 20 pages a month...I would assume he would spend a lot of time out of costume or in silhouette.
Anyway, it turns out he does appear in more than two panels, although only in the background. You really have to hunt and/or read the "Keys to the Kingdom" character annotations to follow Cathedral's storyline through Kingdome Come. Apparently he didn't learn his lesson after his encounter with Wonder Woman and The Justice League, and so he ends up in The Gulag with all of the other "bad" super-people (his leg appears in one panel of a Gulag scene).
During the climactic battle scene, which makes a bit less sense every time I read it (Batman decided the best way to de-escalate the fight between The Justice League and the escapees was to attack them all with his own superhero army?), Cathedral is among the active rioters.
So his final fate is undetermined, but fingers crossed he appears in an Alex Ross-written-and-drawn comic book called Alex Ross' The Cathedral at some point.