As of today (Dec 12 at 2pm CET), 5 new secret achievements were released that were teased in Natarian riddle.
I got one of them, I am very curious to see what the other 4 are.
Other 4 achievements:
Little Picasso: https://gyazo.com/e7adbd6baa755f456b18b48994387508
Fishing (look at mouse on the left side of the screen in the river): https://gyazo.com/b103304a83ded7f0964261b0b63f73ed
No one likes spiders: Release 100 spiders from your village all at once https://gyazo.com/079bc66e4b18d2a318a2670ecaddc541
Oops...: Kill 50 of your own troops while attacking a player you reinforced https://gyazo.com/748a9ebdf61d28df3f42ee9b22604fc9