Ankohl

Ankohl is the name of an ancient, all but dead civilisation, of which Obaba and Eoleo are the last known descendents.

History
The games give little to no specific information on the subject. Although the Ankohl Ruins are located east of Champa and hold a piece of the Trident of Ankohl, they themselves do not hold any further information. Essentially, most information about the Ankohl is fan speculation, and many believe that a future instalment of the series may give some information about it. Along with the Ruins and Obaba's forge, it is possible that the Tundaria Tower and the Shrine of the Sea God are also connected to the Ankhol because these two places both contain a piece of the Trident of Ankohl which is used to break Poseidon's forcefield. It is also possible that Eoleo, who unlocked his Psynergy powers after being hit by a falling Psynergy Stone (in much the same way as Feizhi had her powers unlocked in Golden Sun), inherited the powers of Ankohl, although arriving at this conclusion involves quite a bit of speculation. Speculation on this part can be confirmed, in Dark Dawn, Obaba states that Eoleo is the only one who inherited her powers.

Element
Prior to the release of Dark Dawn, it was widely believed that the Ankohl were a Venus-based civilization, as the Ankohl Ruins heavily featured Sand-based puzzles. However, Obaba (although she is not confirmed to be an Adept), the only known descendant of the Ankohl, has the ability to use an psynergetic forge as well as summon fire-based creatures. More light is shed on this issue in Golden Sun: Dark Dawn, where Eoleo, Obaba's great-grandson, is revealed to be a Mars Adept. Also in Dark Dawn, the Sand Prince is fire based, indicating that the sand puzzles in the Ankohl ruins may be Mars-aligned, instead of Vensus-aligned, as the puzzles of Gaia Rock and Yamata Ruins. As further evidence, the Trident of Ankohl is made to fight a water-based enemy (fire and water are opposing elements). Tundaria Tower (which may be connected to the Ankohl, considering its similarities to the Ankohl Ruins) contains the Mars Psynergy Burst, required for Magma Rock, as well as the Mars Djinni, Reflux. Much of this indicates that Ankohl is Mars-based.

There is also the possibility that the Ankohl were not Adepts at all, but rather, akin to the Exathi of Ei-Jei. Champa is considered a part of the Ei-Jei Region of Angara, and it is well-known that the Exathi and the Neox Jenei of Craggy Peak worked together to make great works such as the Alchemy Forge of Passaj and the Alchemy Well of Ayuthay. It is possible that the Ankohl Ruins, the Shrine of the Sea God, and Tundaria Tower are extensions of the Exathi work around the eastern seaboard. Evidence for this theory would suggest that Eoleo had inherited his grandmother's talent at the forge (an Exathi trait, as opposed to being a Fori with no skills for either craftsmanship or Alchemy), but only got his Psynergy through exposure to a Psynergy Stone.

Quotes

 * In Champa, prior to the Trident of Ankohl's reforging:
 * Champan: You've the look of a traveller about you... Have you been to Ankohl Ruins? (If Felix says yes) Only those who have mastered the powers of the earth can enter the ruins.