He did a writeup of how he did it, here:
http://www.bungie.net/en/Forum/Post/69931884/0/0

-Disciple

Well, after a handful of annoying rumble matches I finished up the void damage bounty so I'll hop into the summoning pits alone as a sunsinger and post results.

Heh, good luck.

There is a room you can sit in to "hide" where a shrieker spawns, but don't kill it. The enemies that come after get much harder.

The problem with Killing the Shrieker is that his death usually equals your death, as his homing bolts can follow you home and fly down the chimney...

You can safely run by it and retreat to the room before it (where you came in) which is what I had to do several times.

This isn't full proof though, because you need to kill the actual enemies supporting phogoth. The ones that spawn in that room don't count- they only spawn to stop campers so killing them gets you nothing!

They despawn along with the Shrieker, which has a ~15 second timer. It's pretty pointless to waste ammo during this period.

:D

The best advice that I can give is to kill as many Knights and gun-wielding acolytes as you can when you first arrive, then work on the melee enemies. This helps control the influx of enemies, and helps keep less enemies shooting at you. From what I've heard, Phogoth can actually damage the others, so there's that. I recommend doing it as a pair, with one person sacrificing himself outside, whittling down the enemies as best as he can until he triggers the third dropship.

When I did it with Rev, I used my super-secret Korny Korner to help take out the enemies and first two dropships while Rev hid in the room behind the Shrieker room, and when the third dropship was approaching, we switched places, so he could pack on the hurt.

When I helped Bonkle, we both actually went after Xyor, which finished him much faster, but is much riskier, since a wipe starts you over from the beginning.

Also, killing Phogoth gets you nothing, which is a real bummer, so go to orbit as soon as you get it.

The hallowed knights are the issue.

Well, after a handful of annoying rumble matches I finished up the void damage bounty so I'll hop into the summoning pits alone as a sunsinger and post results.

Heh, good luck.

There is a room you can sit in to "hide" where a shrieker spawns, but don't kill it. The enemies that come after get much harder.

You can safely run by it and retreat to the room before it (where you came in) which is what I had to do several times.

This isn't full proof though, because you need to kill the actual enemies supporting phogoth. The ones that spawn in that room don't count- they only spawn to stop campers so killing them gets you nothing!

:D

Is Xygor solo-able at 26/27 or do I need to find a group for this? I know people said he was difficult but is it just a matter of him being a bullet sponge or what?

Korny gave me a hand completing this bounty a few days ago, and it is a bit of a challenge.

We did it as a pair- according to him it would have been harder with 3 people as the enemies scale in difficulty (not sure if I've seen that, but that's what he said.)

The actual elimination of xyor is not hard at all- he's just a normal hive wizard, yellow bar (so he takes a little bit more of a beating) with a solar shield.

Basically what you have to do is get down to phogoth, and essentially ignore him. Kill the lesser enemies and the game will bring in dropships to supply new troops.

Xyor is on the 3rd dropship.

What makes this challenge hard is that there isn't really anywhere you can hide. Korny can explain the options better than I can, but if I had to do it again, I would suggest that the person going after the bounty have a high-level solar sniper equipped and an Arc HMG.

You need the solar to cut through the wizards and you need the arc to take off the knights shields. There will be a lot of knights. Killing them helps to spawn the different enemies.

When xyor finally spawns, have the person who needs him, kill him. Wait for the reward text to pop, then quit the mission. You can finish it if you want, but by this point I'd bet you'd be burnt out.