Hello there,
I’ve got a question to someone in the know. I’ve got Grim Dawn with all expansions and those expansions have added more loot. Is the loot pool across the game shared, i.e. can I get Mythical Essence Of Grim Dawn, which was added in Ashes of Malmouth, from running the Steps of Torment or are those items tied to their expansion locations?
I’d very much prefer for it to be the former so I can run dungeons that I prefer, rather than being forced to run one specific one.
No, items aren’t tied to particular expansion areas. Most items in the game are random drops so you could find them anywhere in the game’s content.
Excellent. Thank you for letting me know 
unless grimtools lists a specific source for items “dropped from/sold by” etc at the bottom of the item then it’s random drop from anywhere. So only fixed source drop items forces you to go into XY specific place to obtain them
Expansion tag is not a source just means it needs to be installed
OK, I have to ask. Why so many people think that items added by expansions only drop in expansions? Does a different game do that? It had never crossed my mind until I saw the question coming up on Discord.
I believe it did in Titan Quest(?) at least the post Anniversary edition version
Because it’s a common sense, and one of grimtools impressions
Let’s imagine that you are totally new player, you want find items for you build, and somebody tot you “hey, just check grimtools”
All right, you open grimtools, looking on some item and under their properties you saw “Forgotten Gods”
“So this item drop only in this DLC”, that you thought
You see? Main problem is absence of word ADDED
If on grimtools you will see “added in forgotten gods” then you correctly think that item could drop everywhere, and required this dlc to start dropping
Because of the way THQ Nordic did the expansions for TQ items from the expansions do drop in the base AE version of the game, but they can’t be picked up unless you have the relevant expansion installed.
But as Safarel said it’s most likely because they look things up on grimtools, see the expansion mentioned and think that’s the only part of the game they could find them in.
Somehow I instantly knew it meant “requires expansion, but drops everywhere”, because any other way of doing it seemed silly to me. These expansions change the base game after all. They add masteries available from level 2, Illusionist in the 1st hub, monster totems everywhere. So why would items be restricted to added areas?
This reminds me why I didn’t like the way celestial totems and new areas were handled in 1.1.8.0. Then 
actually followed this strange logic.