First Nareva.
I very much dislike the whole "goddess of secrets" shtick. I firmly believe if someone has access to knowledge that can actively improve lives of many, that knowledge should be shared otherwise i consider it act of gross negligence or just out right malice.
Unfortunately, she
is the Goddess of Secrets (and other things). It's not a schtick. It's what she is. She isn't the Goddess of Secrets just because it's a lark, like she were adding "
boop-boopi-doop" to the end of all her sentences or twirling her hair around her finger. Just like Kinu (farmgirl) might not want to be a princess or high-born or looked to by her people as a leader, but she is. It's what she is and she can rail against it, but it's fundamentally what she will be viewed as, whether she wants to follow it or not. Nereva might not want to be what she is, but she is because of peoples' belief and devotion and intense desires. She was crafted as much as Nereva crafted the salamander race or her avatars.
If she didn't exist, that knowledge would still be lost. It would be gone forever. She
preserves the knowledge, the secrets, the lost lore and desires. It's there for those who strive for it. Who show dedication, drive, motivation, and even a little obsession at times. She isn't keeping it from the world, she is keeping it safe for the world, but just like you don't give a nuclear weapon to an infant or someone who hasn't worked and lost and suffered to obtain it, you don't unleash all knowledge and secrets on the world, or even to your followers just because they worship you. In order to worship her, you should be striving and working and creating and developing with her using gentle nudges, hints, and guidance. Just like she does to the Champ, when they have to pry it from her black, manicured claws.
Who knows how much lost knowledge Nareva has hoarded?
She does, but it's a secret.
If she started to share it, be it steel forging, magic, medice, or just lost knowledge from pre wraith war.
Who would she give it to? Everyone, all around the world? Then now you have nations (because not everyone will be able to make steel, even with the knowledge, because they don't have the right iron, or carbon, or structure to build the forges. Now countries or cultures or races that were held in balance because the bronze age weaponry of their neighbors sweep down and conquer, subjugate, possibly even decimate entire nations or peoples. Guess what that leads to: loss of culture, loss of knowledge, loss of history; stories, poems, architecture, songs, even recipes passed from mother to daughter. And where does all that go without someone to keep it safe and remembered? Oblivion.
If whole secrets domain is at fault, 200 years are plenty to slowly rebrand into just goddess of knowledge.
10,000+ years is plenty of time for humans to learn to work together and live in peace. It's not how it works. Especially since some of that knowledge is dangerous, like portal magic, making magical stones of power that warp and corrupt their users, advancing a culture too quickly.
But no, she just hoards and her organisation just pesters magicians too powerfull.
Her order hunts down mages dealing with overly-powerful magics or world-altering magic. They might be overzealous or occasionally stormtrooper-like as they investigate, but someone able to manipulate and move massive structures via the Ways Between or open portals or warp the bodies and souls of normal creatures without transformative alchemy is worth investigating, and possibly stopping. They weren't kicking in Ivris' alchemy shop doors and stomping on all her magical milky-boob and penis-growing fruits.
Not to mention the convocation thing. Keeping someone alive in dreamlike state forever, sounds just cruel to me.
What do you think death is like normally? She's not keeping them alive. They are dead. She's keeping their consciousness and learning and essence alive. She's keeping alive that which was (Ander's) goal and life and desire and greatest accomplishment and giving him the opportunity to see it come to fruition, to see it grow, to see it possibly used to save the very world. His sister was a by-product and casualty, but the alternative is not better. She never got to lift her sword or face her foes. Now she can (but that's your choice, not Nereva's, she only created an opportunity).