I'd been expecting Arhu to show up at some point via this Black Cat but each playthrough I either lose him due to teleporting / area transitions / vine and ladder climbing, or he gets slaughtered by a random Magister.

I've read rumors about it being related to an unimplemented quest we'll see on official release. It'd be neat to see Arhu at some point. Since you know... Arhu is like thousands of years old and whatnot. Can only assume.

In my line of work, it's never a quiet day on the market.