There are times when theories like this keeps me up at night. Menzies currently rules the Underworld and Fissure of Woe.
Throughout the lore of Tyria there is one major entity that has never been fully flushed out before, Menzies has been a footnote on story elements with being sparsely mentioned and only ever seen in 3 places. The shadow army has only ever been seen in the Tomb of the Primeval Kings, Fissure of Woe and Realm of Torment. The only known leaders of the shadow army are the Priest of Menzies(fought in the Fissure of Woe), Shakahm the Summoner(fought in the Domain of Secrets), The Darkness(fought in the Hall of Heroes) and the Greater Darkness(fought in Ravenheart Gloom) and the only information we have of the God himself as that is is/was at war with Balthazar in the Fissure of Woe and that he agreed to join his forces with Dhuum’s and Abaddon’s army(against the dragons but thats another lore theory).
but thats all from Guild Wars, what about Menzies in Guild Wars 2? The Fate of Menzies, a torch, that you get from the mystic forge… thats it.
Well, then lets see what we know about the shadow army and their activity. every member is “Shadow class” or “noun of Darkness”, in Guild Wars 2 the only major boss that is shadow army esque is the Shadow behemoth, as far as foot soldiers go we only see “Shadow Fiends”, and those 2 aren’t even labeled as Shadow Army.
The Shadow Army hasn’t operated on the Tyrian plane of existence(hystorically) so what actually happened? My theory is simple. Abaddon is dead, Mallyx is dead, the major military leaders in the Domain of Anguish are dead, Dhuum has been forced back into hibernation. Menzies in the chaos of events seized control of the Demon army and Underworld army. Shadow creatures appearing from Underworld portals, but the final nail in the coffin comes from Balthazar himself. if you’ve visited Auric Basin your aware of the Statue of Balthazar focus point, its less then pleasant to try and get as most of the time a difficult event is blocking it. an Avatar of Balthazar and 2 Hounds of Balthazar. This statue, was in Guild Wars 1, if you knelt at the statue you would summon a Champion of Balthazar who would offer to transport your party to the Fissure of Woe for a fee, even more compelling is that in Lornar’s Pass there is a Statue to Grenth guarded by Shadow Fiends(Shadow army) and Aatxe(Underworld army). in Guild Wars 1 you could do the same thing here, kneel, pay a fee, go to the Underworld.
Menzies is controlling 3 armies, operating them across at least 4 different dimensions(Tomb of Primeval Kings was a gateway to the Hall of Heroes, where you fought the Darkness as an end boss), seemingly guarding to prevent access to any of these dimensions to anyone. the Shadow Behemoth events are the fallout from the destruction of the Temple of Ages, which historically served as a hub where humans would cross dimensions with the help of avatars of the gods.
If you played Guild Wars 1 as long as some of us did, when Guild Wars 2 launched then you where disappointed that both the Fissure of Woe and Underworld are missing, ArenaNet says “because they aren’t ready yet, but will be added in the future”, but as far as lore reasons, Menzies isn’t letting us explore there anymore.