Olthoi Arcade has a new extension.

The new branch has at least 4 levels I can tell.

Unlike the first 2 dungeons, this arcade ascends (you run up)

Nobles > Eviscerator > Warriors > Mutilators

I couldn't make it far into the mutilator portion before I had to recall.

Eventually myself and an archer made it to the end. A portal back to the second portion of the arcade was the only thing we could find.