A cliffside cave was located halfway down a sea cliff on the Island, accessible only by a series of dangerous rope and bamboo ladders that extended from the top to a narrow ledge near its entrance. It was first revealed in "The Substitute", when the Man in Black took Sawyer to the cave see his name written on the wall. This was one of two locations where a list of Jacob's candidates was found.
The history of the cave or how it came to be occupied is unknown. It is unclear if the cave was man-made or formed by natural processes. In "The Substitute", the Man in Black implied that Jacob was aware of this location and came here from time to time.
In 2007, shortly before the attack on the Temple, the Man in Black brought Sawyer here to the cave to show him the list of names scrawled on the cave walls. On entering, the Man in Black picked up the white rock off the balance scale and hurled it out the entrance of the cave. When Sawyer inquired about his action, the Man in Black referred to it as an inside-joke between himself and Jacob. ("The Substitute") The cliffs were the location of the final battle between Jack and the Man in Black. The battle ended with Jack kicking the Man in Black over the side of the cliffs, leading to his death. ("The End")
The cave entrance opened out of the side of a sea cliff and could not be seen from above. Access was gained by making one's way carefully down to the very edge of the cliff where the top of a dangerous rickety bamboo ladder was found. The ladder appeared to be one of several segments: one descended the first ladder before transferring onto a rope ladder which was somehow anchored into the cliff. There also appeared to be a third segment below. The bottom of the ladder reached a wide ledge which led to the cave entrance. In 2007, the ladder appeared old and in bad condition based on Sawyer's near-accident. ("The Substitute").
Immediately inside the entrance was a low table containing a number of artifacts, including a balance scale with a white stone on one side and a black stone on the other. Other objects included a lute, mortar and pestle, and a baseball bat.
Following the passage further in, the cave opened into a larger room or cavern. The rough irregular walls and ceiling of this chamber were covered in hundreds of names, each scrawled by hand and associated with a number. It is not clear if there were other passages or exits from this chamber.
The vast majority of names had been crossed out at some time in the past. Six names that were not crossed out stood out from the rest:
According to the Man in Black, Jacob wrote these names here. Allegedly all of these individuals were candidates who might replace Jacob as protector of the Island. When Sawyer asked about the corresponding numbers, the Man in Black responded, "Jacob had a thing for numbers." While the two were talking, the Man in Black crossed Locke's name off the wall. ("The Substitute")
Why Jacob would keep track of his candidates on the walls and ceiling of a cave is unknown. Given the Man in Black's obvious bias against Jacob, however, it is worth taking his account with a grain of salt. A strong case could be made that this was actually his cave. Given that Kate asked Jacob about why her name on "the wall" was crossed out (in "What They Died For") and Jacob answered her, this suggests that it could be in fact Jacob's cave.
- While Kate Austen was not seen to be one of the candidates, Carlton Cuse said in a 2010 Paley Fest interview that her name did appear on the wall crossed out, making her a former candidate, and he apologized for the footage not making the final cut.
- The name "Straume" is seen crossed out on the cave wall. As Miles was still alive this implied that individuals could be crossed out for reasons other than death. Similarly the name "Littleton" was also crossed out on the cave wall, although both Claire and Aaron were still alive. In "What They Died For", Jacob eventually revealed to Kate that "Austen" was crossed off because she was a mother. This is possibly also why Claire's name was crossed off.
- In "The Package", the Man in Black told Claire that her name was not on the wall and also that Kate's name was not on the wall any more.
- Many of the items seen in the cave were similar to articles seen in Dogen's office at the Temple.
- Sawyer clearly left the cave by "Recon" implying there was another way out of the area that was not the original ladders (the ladders could be seen still broken by the The End); a ladder leading to somewhere else is visible in the the inner cavern.