The Hand of Arlen (아를렌의 손, Aleullen-ui Son) is part of what was once a massive statue, located near a Tent Village on the 28th Floor. It resembles a gigantic stone hand rising out of the ground.
The Hand of Arlen are the remains of a huge stone statue that was broken. It used to be a base for criminals, but it got cleaned out by the authorities some time ago and is now deserted. Because of it, the area surrounding Arlen is infested with traps and monsters such landmines and stone golems. Beniamino Cassano once resided there.
Following the events of the Devil of the Right Arm arc, the Hand of Arlen was eventually blown up by Xia Xia in an attempt to kill Koon, Ran and Novick and to remind Jyu Viole Grace of his allegiance to FUG.
The first love of Zahard and the "mother" of Baam was a woman called Grace Arlen, the same name of the statue. The statue as a whole was likely a statue of Arlen that was destroyed during Zahard's purge. The hand is seen in Garam's flashback.