I created this Image to show the stages to get the Hoard Mimic:
You need to get lucky to get the Mimic battle from Mythic Boss Battle, then you need to be super lucky again to get the Hoard Mimic battle from the Mimic Battle, then super super lucky to get the mythic drop.
Updated Image
Guys based on my data and that of my friend @Cronus, I computed the probability of getting the Mythic. It’s only an educated assumption, not concrete numbers.
Stage 1: Getting Mimic Battle from Explore chest = 10%
Stage 2: Getting Hoard Mimic Battle from Mimic Battle = 5-10%
Stage 3: Getting Hoard Mimic Mythic drop from Hoard Mimic Battle = 5-10%
Your Probability is now known as Compounded Probability.
Normal case = 0.1 x 0.1 x 0.1 = 0.001 = 0.1%
Worst case = 0.1 x 0.05 x 0.05 = 0.00025 = 0.025%
Meaning:
In normal case scenario 1 out of 1000 (Explore Chest)
In worst case scenario 1 out of 4000 (Explore Chest)
Good luck everyone
Super Grindy!
@WhoDat These are our current updates rates, again among three friends.
| Mimic | Hoard Mimic | (from mimic boss) | (from hoard mimic boss) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Account | Difficulty | Boss Chest | Boss | Chest | Boss | Chest | Drop | Mimic Rate | Hoard Mimic Rate | Hoard Mimic Drop |
| Account #1 | Varies | 1387 | 151 | 131 | 25 | 21 | 1 | 10.89% | 19.08% | 4.76% |
| Account #2 | Varies | 1544 | 146 | 139 | 22 | 14 | 1 | 9.46% | 15.83% | 7.14% |
| Account #3 | Varies | 719 | 72 | 64 | 13 | 5 | 0 | 10.01% | 20.31% | 0.00% |
| Total | Varies | 3650 | 369 | 334 | 60 | 40 | 2 | 10.11% | 17.96% | 5.00% |
We finally got this in two accounts (I and one of my friends), the third one is still searching for it. Some points:
Just a small correction to your numbers: the total probabilities you are stating are either 0.1% or 0.001 for the normal case and 0.025% or 0.00025 for the worst case. As you state in your explanation, 1 out of 1000 or 1 out of 4000. The probability of 0.001% would be 1 out of 100000 - that would be a disaster 
Also, an additional information (I hope, my math is right on this): if we assume the best case of 0.1%, this would mean, that you have to collect a total of 4603 explore chests to have a chance of more than 99% to get at least one hoard mimic. If we assume the worst case of 0.025%, you would have to collect a total of 18419 explore chests to have a chance of more than 99% to get at least one hoard mimic. The first number seems kind of ok for me, could be doable within this year. The second number… well, this is not doable within this year 
Am I reading this right - out of 369 mimic you managed to get the hoard mimic 60 times? If so, did you notice any significant reduction in chances to get the hoard mimic recently? Did you record kingdom and difficulty level when the mimic chest turned into a hoard mimic?
I’m really curious, because right now I believe I’ve had about 150-200 mimic encounters on E12 chasing the 20% mythstone bonus since last week, and yet only 1 hoard mimic encounter.
I have not recorded difficulty and kingdom of individual runs. Although most of these runs happened either in Wild Plains or Broken Spire and on E1/E9/E12 difficulties. I know this because these are the go-to kingdom and farming combinations I and my friends use.
60/369 is not the right way to read this though. If you look at the table again, you will see that we faced mimic 369 times, but we only managed to win the fight 334 times (opened the chest). If you don’t win the fight, you cannot really know whether it would turn into a hoard mimic fight or not, so that is not included. In other words, the hoard mimic turn rate is 60/334 (or ~18%). Did this change recently? I would not know. I have the approx. dates of each individual session that we have recorded, so I could take a look. Is there a particular date you are interested in?
(I really don’t expect any change, but still happy to crunch numbers)
I´m curious, you encountered the Hoard Mimic 60 times and lost 20 of these battles, correct? I assume, this happens, as you just don´t adapt your team to the Hoard Mimic battle and run into it with your “standard” farming teams. What is the reason for this? You don´t care for lost Hoard Mimic battles, as you farm so much, that you will encounter them many times a week and finally get the mythic anyway? I mean, basically, if your rates are correct, it could well be, that you “wasted” a third mythic drop with the 20 lost Hoard Mimic battles
Yes, that is correct. We play so much that most of the time, especially while trophy farming, we pay very little attention to the game itself. Moreover, almost all the time, we also do something else e.g., watch something else.
Our E9 farming team is capable of killing all enemies in a single cycle, however if this does not work (e.g., against L150 mimics), then you have to refill the cards, which take some time and manual effort. This is generally when we realize that it is a mimic battle (when mimics don’t die). Also, we had horrible chance with (hoard) mimics devouring, hence making the fight even more difficult (again considering that we don’t change teams, it could have been much more easier if we did).
Considering how much we play, we were very confident that we would get it eventually. So, it is really a matter of when. Doing what we do delays the inevitable, but so far worked alright for 2 of us 
After all, you really need the hoard mimic mythic once, and definitely no more than 4 times.
As a final side note, I was doing the runs so mindless that I actually did not realize when I got the mythic drop (yes I also pay no attention to rewards). I only realized this when I was checking something else on herolookapp and then realized that I could enable another power level for Dragon’s Claw. I could not believe first and it was super surprising to see hoard mimic in available cards 
Lol, amazing approach 
That would never work for me. I do also watch other things while farming for example E12, but to be honest, either I watch something, that is not really interesting for me, so my focus remains on the game and I could as well just play without anything else or I watch something interesting, then my focus gets drawn to whatever I watch which results in reduced performance in the game.
Anyway, thanks for the explanations 
It’s surprising to me that you encountered the hoard mimic that often, even more often than I initially though with the adjusted numbers. From what I’ve seen you are the only one who have recorded your runs in such detail, so I can only compare my experience to your numbers.
Unfortunately I don’t have a specific date I could ask you to look up, since I only started regularly running E12 last week to try to get the troop. Before that it was only sporadic attempts every now and then.
After my previous post I started tracking myself. Unfortunately I haven’t had as much time this week to grind so the numbers are currently very low. I can only assume that I accumulated somewhere around 5k trophies from E12 before starting to track my success rate. At this point I’ve opened a total of 67 boss chests, of which 10 were battles against the mimics. 0 hoard mimics so far.
I’m only a few tokens shy of my third Nysha medal from grinding, and yet I’ve only had a hoard mimic battle one time. Could be differences between platforms, but I kinda have the feeling they adjusted the chance of encounters sometime last week, which was why I asked if you had noticed any drops while you were tracking it.
Fair point, I will see if I can break down things a bit more. It would be surprising (but not completely unexpected) if they lowered the chance (that was already low), but who knows
Here are my stats so far.
1200 boss chests
116 Mimic chests
17 Hoard Mimic chests
No Mythic drop so far.
I believe these numbers as very close to the percentage I put earlier. @Campo
10% chance you will get mimic battle from boss chest.
Another 5-10% chance you will get Hoard mimic battle from mimic battle.
Another 5-10% chance you will get the mythic drop.
These are based on my numbers. I done over 2000+ boss chests.
My friend @Cronus numbers properly more accurate since he done more battles and more data.
Good luck
Updated rates on our end:
| Mimic | Hoard Mimic | (from mimic boss) | (from hoard mimic boss) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Account | Difficulty | Boss Chest | Boss | Chest | Boss | Chest | Drop | Mimic Rate | Hoard Mimic Rate | Hoard Mimic Drop |
| Account #1 | Varies | 1633 | 155 | 140 | 31 | 21 | 1 | 9.49% | 22.14% | 4.76% |
| Account #2 | Varies | 1879 | 191 | 168 | 29 | 17 | 1 | 10.16% | 17.26% | 5.88% |
| Account #3 | Varies | 935 | 86 | 72 | 19 | 5 | 0 | 9.20% | 26.39% | 0.00% |
| Total | Varies | 4447 | 432 | 380 | 79 | 43 | 2 | 9.71% | 20.79% | 4.65% |
A few highlights:
Finally, there was some discussion whether the drop rates were changed or not recently. Below is our data starting from the beginning of vault week (03/14/2022):
| Mimic | Hoard Mimic | (from mimic boss) | (from hoard mimic boss) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Account | Difficulty | Boss Chest | Boss | Chest | Boss | Chest | Drop | Mimic Rate | Hoard Mimic Rate | Hoard Mimic Drop |
| Account #1 | Varies | 1032 | 101 | 91 | 23 | 17 | 9.79% | 25.27% | 0.00% | |
| Account #2 | Varies | 1246 | 126 | 103 | 18 | 7 | 10.11% | 17.48% | 0.00% | |
| Account #3 | Varies | 614 | 52 | 42 | 12 | 3 | 8.47% | 28.57% | 0.00% | |
| Total | Varies | 2892 | 279 | 236 | 53 | 27 | 0 | 9.65% | 22.46% | 0.00% |
According to this, I don’t see much change (I did not even include drop rates here since we don’t remember when we get the drop).
@Campo Thanks for your numbers! Are you on PC, btw?
@Cronus Thanks for the update, your numbers are still quite consistent. I guess I’ll just keep trying and maybe it will even itself out for me down the line.
No problem! I play on Xbox.
