The Yenbenmirra are functionally unplayable- Even by migratory standards.
I wanna start this post with saying that the mechanics at play ARE COOL, the design IS ENGAGING, I respect that a lot of work went into these, and I AM the target audience!
(a native tribes (vanilla EU4 and Anbennar) enjoyer, even playing them in MP!)
I WANT THEM TO WORK!
But right now, the numbers are an absolute mess, and the tags are broken (not in the fun way) as a result.
Issue 1: Mana Balance
As you might be able to inference from the image, these tags are quite admin heavy, leaving you with a massive surplus of diplo points (you use a decent amount of military to migrate)
You cannot do anything worthwhile with these besides increase mercantilism or take diplo tech, at a certain point however, taking the diplo tech results in imba research just cause you don't use any.
This is only annoying at the start, as you scale upwards into trying to reform however, this becomes EGREGIOUS, with tribal land costs upwards of 500 ADMIN FOR 1 PROVINCE, where you need 30 to reform. Taking your govt reform to even start approaching that goal of 30 provinces while still collecting mechanim is also a noob trap, making the tags even more slow and unenjoyable, and potentially softlocking you by having no mechanim you can expand to before tribal land costs are above your admin cap.
Issue 2: Children of Fire
The coolest mechanic of the region, and unfortunately, also a broken one, due to the limited dormant mechanim in the region, the way you expand is extremely border-gorey once settling (bad juju) and any alliances you have with kobolds or fellow Yenbenmirra must be dissolved, due to both of them often taking over your desired dormant provinces. This alone is annoying, but workable, where it becomes truly broken however, is when the Yenbenmirra and Kobolds (or Islanders) end up fighting, the Yenbenmirra will lose, and their collected mechanim will be gone, forever. The tags are softlockable, and it's not an uncommon softlock given by 1520, I had already seen 2 tags die to the AI.
Furthermore, by being locked to 200 per war, its very easy for them to die while waiting between truces, as you don't want to trucebreak due to-
Issue 3: Religion
As the religion requests you have good relations with the others, for things like mana, manpower and more, this unfortunately cannot be maintained due to the AE from seizing children of fire and tribal land from your neighbors in order to form in the first place, especially since, as mentioned earlier, many of these tags will expand into the provinces you need, and wipe out the tags you need to steal from. All in all this is definitely the lesser of issues on its own, and if the other two were attended to, might be workable.
Issue 4: Forming
This isn't even really a big issue, but trying to dangle a reward for every 1000 children of fire I collect OVER 6000 before forming is honestly an insult, given how it takes well over 100 years to even get 4000-5000 (still not enough to form) in the first place. Like you're asking me to spend another 50 years chasing down more provinces at absurd admin costs for the tiniest bonus, you could genuinely make the reward like 10% all power cost and it still wouldn't be worth it, it's just that absurd as is.
Suggestions:
Lower Requirements- While this doesn't actually solve the issue of potential softlocks, it makes them less likely, by lowering the required provinces and children of fire, it makes the formable more consistently achievable with less horrible suffering on the part of the player
6000 -> 4000-5000 (While 4000 might be a bit extreme of a drop, I think it helps the tag keep pace with it's gameplay, instead of having a 50-100 year waiting period of checking in every 10 in game years to take a singular province towards your goal, as it's around that point that things slow down DRASTICALLY gameplay wise for you, as the formable dangles the renaissance in front of you.
30 Cities -> 15-20 Cities (Same reasoning as above, but with raw admin costs instead of scarcity issues)
Change Dormant Mechanim requirement- On collecting children of fire, instead ensure there's a minimum amount of 100+ scavenged + X per dormant mechanim provinces on usage, this ensures that a softlock cannot happen due to tag deaths, and potentially stops having to go through the same provinces many, many times due to adjacent dormant mechanim.
Dear people still reading, please give the tag a try yourself! It's a cool way to play migratory, and I think the devs cooked on this concept wise, but it still needs a little more work, and I hope the community can fix it sooner than later! If you have any suggestions, add them below!