Any updates?

No, unfortunately not.

Try turning it off and on.

It Happened to me too. After completing the quest line I went back to where the finale took place, then I dropped off some stuff at my mage tower. After that I went right back to the priory and they were all gone. This is the only thread I could find mentioning the bug or whatever it is.

Warden, never had the knights go invisible (could you interact with them if you clicked in the invisible space they were supposed to be?)

But this dlc is full of bugs. I got the one where sir gukimir follows you around everywhere like the kid from the arena, only you can't tell him to just wait here or to return to your duties. :-) And he's mortal.

You'll likely need to use setstage to advance the quest a notch... look up the whatever quest of the nine you're after by it's quest name on uesp.net to find it's refID and stages... I would also install the unofficial oblivion patch if you haven't. It supposedly fixes a lot of the common bugs with this dlc, and all of the game. (sadly not all of them)

Sounds like Graphic issue or pc Resource issue, as above point out, never seen this myself.

Loot load order and Unoffcial patch , should be Mandatory, ( this is just like skyrim, and most issue is this wrong loadorder then apply more mods. )

there should be a most read first at this forum.

holy daedric weenises I should look at posting dates sometimes, I didn't notice Oh Yeah was a master necromancer! Didn't you know the Mage's Guild banned necromancy!?

Just so I'll clarify for future questions as to this problem. The Knights of the Nine are not invisible, they're were entirely missing. I had completed the entire KOTN questline and no knights had died at all during it. It is not a graphics issue or even corrupted load file at all. I have not been able to find out what the issue is and such have started a new game. I've not run into the issue since but I do suspect it was a bug that had come up in the system. I also have all the unofficial patches for Oblivion including the Shivering Isles and the Extra DLC for the fighters guild keep and Frostcrag tower and the rest.

Pretty much the same exact thing here. While I don't know about them being invisible or missing they sure seem just missing to me and I'm not familiar enough with console commands to prove one way or another. They all went missing after the KOTN questline was completed and none of them died. I also have the Unofficial Oblivion Patch and the most popular texture pack on Nexus and tried turning them off, but that didn't fix the problem. I also have all the DLC.

If you use the 'moveto' console command it can be used to locate where certain NPC's are. I recommend taking a look at either UESSP which is the unofficial guide on everything. Or you can use Bethesda's fandom guide on console commands

not sure whats its about, but work as it should in my game. ( it compleated ofc. now. )

I know this is very late, but if you type prid then enter their reference code to select the knight you want. Then use the enable command followed by the moveto player command it should work. Their codes are as follows.

Carodus xx0016e1
Areldur xx0021fa
Avita xx0026a1
Thedret xx001443
Brellin xx00267d
Gukimir xx002686
Geimund xx002686
Lathon xx002699

Replace xx with the load order number of knights of the nine for me it's 02.
Hope this helps a fellow Crusader in the future.

Never had that problem, I only unable KotK after the main story so the church is not a mess from the start.