Hello fellow locks,
I am coming here in hopes of clearing up some information that I have been reading on WoWhead and to maybe see why Blizzard has been a little weird with how they have answered my questions regarding this item and the quest line.
Xorothian Firestick is a gun that drops from Immol’thar, the final demon you kill in the legacy warlock quest chain for the level 60 dreadsteed. I have a had requests from a friend to run him through Dire Maul after he noticed on WoWhead (link above) that players were still summoning this demon and killing him.
It’s all in the comments on the how and what to do.
My main question came after I went to the NPC mentioned to purchase the items on my warlock (who has the legacy achievement). When I noticed I could not purchase these items, I put in a ticket to see if this was removed from the game or if it was just a bug. After three tickets, I couldn’t get a straight answer. I have also posted on other forums and the best answer I was given was to basically ask the player base. So here I am…
For any Warlocks out there that have the legacy achievement Dreadsteed of Xoroth can you purchase the required items and kill Immol’thar?
If you look through the comments, you will see that players are still talking about summoning Immol’thar through 7.0 into 8.0 so feasibly, it should still be good to go?
It’s still possible to summon him under a few conditions.
Condition 1 - The Warlock must be attuned by the questline, this mean if you didn’t do it, sorry you can’t summon it.
Condition 2 - The Warlock must already have the mats, because its no longer possible to buy them, this mean you need to have them from way back then.
So yeah, it’s extremely rare due to those 2 conditions.
Edit: it seems there is another way? on the wowhead page, comment from 7.3.5 by [Tsanov]
@Malacath
I’m still going to look into it some but it is starting to look like your first 2 conditions are correct. I was thrown off by Nirv’s comments (Patch 7.0.3). It sounds like at the beginning of Legion, you could still purchase those items if you had the attunement. ( He mentions going to Burning Steppes and talking to Gorzeeki Wildeyes for the purchase)
Maybe that option was removed? I think that’s what I’m looking for; Was there a way to purchase these items as recent as last expansion (Nirv comment) and if so, was it confirmed to be removed or is a bug? i thought blizzard would address if it was bug but they have yet to acknowledge that the purchase of these items actually existed. (If that makes sense)
I still have the items on an old warlock but she’s Horde. 
Yes I just checked, the goblin has the items for sale for me. I’m looking at them as I type this.
Okay, so then this would be a bug?? @Kronides Thank you for sharing this. I’m curious why i can’t get any blizzard rep to acknowledge this, or maybe this isn’t supposed to be a thing? Or maybe it had to be the original character? Are you on the warlock that you completed the original quest with?
I don’t think it’s a bug; as Malacath says above, the warlock must be attuned by the quest line to summon, and therefore presumably to see the vendor objects as well.
And yes, this is the same guy, I never have changed characters.
Good luck, I wish I could be more help to you.
Thanks for checking for me. My lock is attuned. It’s why I thought it might be bugged cause I should have access to it but I wasn’t on the lock that originally unlocked it so I’ll try that. Appreciate the time everyone. Thanks again.