There is no completist badge for Aranna, because Aranna itself is not complete. Aranna is currently only half-imagined, which is why Rook attacks are so common there. I presume the devs will introduce a completist badge once all the streets are unlocked.
Aranna was the focus of street projects before the final beta reset, so it is in no way complete yet (hence the rook attacks and the half-imagined area map) until the projects resume, I think.