Hadja

She becomes available to purchase tokens from after completing This Old Waystone.

You should get a soulbound item depending on your loot spec out of https://www.wowhead.com/items/quality:2?filter=82:195:64;2:1:1;90200:0:100#items;0+15+19 (not sure about [item=190374], haven't seen that one).

These items have a chance to proc a tertiary stat (speed, leech, avoidance) and/or a socket if applicable (probably head, neck, wrist, waist and finger).

Buying these items and selling them back to a vendor isn't the greatest way of converting your Anima into gold, you get between 5 silver (necklace) and 20 silver (2hand strength weapon) per Anima, compared to almost 50 silver if you buy [item=185765] (with the EU median price of 350g at the start of 9.2), but it's a decent way to make some quick cash if these reagent prices drop, using the AH is too much hassle or when gambling for a speed set.

Note well that the drops from bosses or quests in the open world provide zereth-mortis specific powers for hands and chest for sure, helm afaict also. So you might want to avoid burning anima on those.