Arka is an a priori conlang (naturalistic artlang to be exact) with more than 15,000 words and its own conworld. It started in 1991 in Japan.
It is known among conlangers in Japan but is little known abroad because sites on Arka are written in Japanese.
We hope you will be interested in this language. It would be very helpful if anyone would inscribe Arka on a list of conlangs.