The Subterra is the underground areas of the Pharos at Ridorana. The only way to access it is by finishing the Pharos event first.
To enter the Subterra, players have to use the Dais of Ascendance located at the center of the Pharos near the Gate Crystal. It will take players down to the first level, Penumbra. From there, players need to obtain Black Orbs to unlock the entrances to the other levels: Umbra and Abyssal.
It is recommended to have strong weapons, armor and accessories that guard against Confuse. It is also useful to stock up on items, especially Vaccines, Phoenix Downs, Antidotes and Eye Drops just in case a Ribbon is not available. Gambits for Arise, Steal and Curaja are also useful. Also, it is strongly advised not to equip the Diamond Armlet while searching treasures in Penumbra, as it will turn the treasures into a Knot of Rust.
Many treasures can be only one item, however, where it doesn't matter if the Diamond Armlet is equipped or not, and there is a treasure in the middle of the southern portion of Umbra that is a Megalixir but only if the Diamond Armlet is equipped. The treasures that always contain good equipment have low spawn rates of 30% per entry and will never respawn. If the treasure turns out to be gil it is only 1 gil, or 2 gil with the Diamond Armlet equipped.
The player needs to collect Black Orbs and place them in the pedestals in rooms in every corner to make the next level available (see the Black Orb article for a number of orbs needed per pedestal). The Phoenix can be fought at any time. It is not required to light up all the rooms already to fight Phoenix, but it is recommended. The Massive Black Orbs found in certain rooms make obtaining the required number of orbs easier. If a Black Orb is left alone it will join the Massive Black Orb, but adds to the Massive Black Orb threefold, thus quickly accumulating in number.
After lighting up the pedestals in the Abyssal floor, a new destination appears at the Dais of Ascendance. If the Phoenix has not yet been defeated, the player is prevented from reaching the final area by a "mysterious force" and returned to the the First Ascent. If the Phoenix has been defeated, the mysterious force disappears and allows the player to access a new floor, which contains the hunt mark Shadowseer, if the bill has already been accepted from Montblanc.
This floor is only accessible preceding the Shadowseer Elite Mark. After the hunt is completed, the player cannot return to Hell's Challenge.
- Magick Pot
- Dead Bones
- Zombie Warlock
- High Reaver
- Bull Abaddon
- Dragon Lich
- Vagrant Soul (Rare- appears after Shadowseer is defeated)
- Luxollid (Rare - appears after Vagrant Soul is defeated)
- Phoenix (Optional Boss)
- Ixion (Elite Mark)
- Shadowseer (Elite Mark - appears after Phoenix is defeated)