A Bahro Cave is a small cave created by the Bahro. It is illuminated by lamps hanging from the ceiling.
Most of the Bahro caves are located over a Starry Expanse, which links to Relto. There are however two caves located above the Rudenna district of the D'ni cavern. According to the KI even the caves above the starry expanse are located in Rudenna.
There are two pillar caves, both of which are part of Yeesha's quest. Both of them feature four rock plates arranged in a circular pattern that can slide out of the wall. In the middle of the plates is a hole leading down. The caves can be accessed via the Journey Doors in Gahreesen, Teledahn, Kadish Tolesa and Eder Kemo. Each door links to one of the four sides of the cave, at which the corresponding plate will extend to make room for the player to stand on.
On each platform is one pillar corresponding to the age and a symbol that is part of a combination necessary once returning to the Cleft. There are also two touchable symbols on the cave wall. The first symbol is a hand symbol used to transport the pillar, and the second one is a drawing of Yeesha, which will play her speech for the corresponding age.
The first cave, illuminated by blue lamps, originally contains the pillars. By touching one of the hand symbols, the corresponding pillar will disintegrate, fall into the starry expanse below and land on Relto. As the Relto book does not work inside the cave, the player will have to also jump down to get linked to Relto. The platform on which he stood will then retract again.
When all four pillars have been brought to Relto, the journey doors will link to the second cave. This one is illuminated in orange. By touching the hand symbol there the pillars are transported from Relto to the cave. Because the Relto book doesn't work here either, the only way out is through the hole below into the D'ni cavern. Although there is no starry expanse below this cave, the player will still be linked back to Relto. After linking out the rock platforms stay extended, unlike in the first cave. This makes it possible to later read the symbol combination on the platforms. With every pillar returned into the Bahro cave, a Star Fissure on Relto will grow. It will fully open once all four pillars are returned and can then be used to link to the Cleft.
There are four wedge caves, each one containing one row of wedges for Relto. There is one cave for the garden ages Eder Delin and Eder Tsogal, one for the Pod Age, one for Minkata and one for Kadish's ages Er'cana and Ahnonay. Most of the caves can be reached through a portal in the corresponding age, except for the Delin and Tsogal ones, which can be accessed through the journey doors in those ages.
The wedge caves are similar to the first pillar cave: they are illuminated by violet lamps and have as many rock platforms as ages, which retract again after linking out. On the cave wall is only one symbol per platform, which is different for each cave. When touched, the corresponding wedge will disintegrate, fall into the starry expanse below and land on Relto. The player again has to follow the same route, because the Relto book doesn't work here either.
There is only one pellet cave, reachable via Bahro Stones in Er'cana and Ahnonay. It is very different from the rest of the caves: there is no hole at the bottom, no objects to collect and no symbols to touch. It is simply a cave with two floors.
On the bottom one, reachable via the Bahro stone in Ahnonay, there is a small basin that seemingly contains algae similar to that in the cavern's lake. If a well-baked pellet from Er'cana is dropped in there from the upper floor, it will light up the walls, revealing many Bahro Glyphs and a combination for the imager in the Cleft.
On the top floor are only three symbols indicating the oven settings to bake a good pellet. Because the link-in spot is right next to the hole, pellets can be dropped from here into the basin below.
Unlike in the other caves, the Relto book will work here. There is also no other way out.