Yes, WaniKani is on there.
Anyway, here is the link to an interesting post on duolingo with a compiled list of resources to learn Japanese from.
We have our own Ultimate List of Resources. Better yet, there’s no homicidal bird in sight. 
That guy’s got the Tofugu logo as his avatar image, so it’s not all that surprising that he recommends WaniKani.
Technically, you can use adblock, a free ad blocker, to just delete all of the duos.
It works!
And besides, Duo is genocidal, not homicidal. But thanks!
He has mastered the way of the owl.
Just choose one or two languages and learn them properly 
Definitely.
(Did you notice he is learning klingon?)
I did not 