By which, of course, I mean the Glyph of Felguard.
What’s it do? Simple:
- When this glyph is equipped, your felguard will equip a random two-handed axe, two-handed sword, or polearm from your backpack.
Despite the name, this does in fact apply to Wrathguards too - they’ll equip two random weapons from those categories from your backpack.
They don’t actually equip it, of course, because then demonology would be rolling on two-handed axes and swords as DPS upgrades. It simply copies the graphics for the weapon in question. It does, however, only equip it once. If you want your wrathguard to wield two of the same weapon, you have to have two of the same weapon in your backpack.
Note that it specifically excludes two-handed maces. No felguards wielding Sulfuras (either one) or, more tragically, The Shoveler. Sadly, the mace restriction means I can’t have a wrathguard wielding my namesake weapon, but I guess we can’t have everything with a glyph this awesome.
Enchantments on the weapons will not show. You can put anything you want onto the weapons in your backpack - they’re only copying the base model. This also means if you want a glowing weapon, you’ll have to find weapons with an innate glow.
Note that it also specifically says your backpack. None of your other bags will do, just the original unreplaceable 16-slotter. This does mean you can have up to 16 weapons for your felguard/wrathguard to choose from at the same time. Think of it as your personal demonic armory.
Also worth noting: you can equip things that you couldn’t legally transmog into if you could equip them. Example: my warlock can’t equip any of the old level 60 PvP epics because he wasn’t around in vanilla to earn the titles, but I can buy a High Warlord’s Pig Sticker and let my demon wield it (and have done so). You can also put white and grey-quality gear in there and as long as it’s the right item type, they can use it.
A good starting place to find some easy-to-get, good-looking weapons for your minion is Rades’ list of non-raid weapons. It doesn’t include things from the very newest content (revamped Scholomance, RFC and SM), but Wowhead has you covered.
In case you were wondering, here’s my current weapon list: