Apru (pronounced AH-proo) is an ancient Eitan colossus who began life as an elf living on the aerolith Nensa. From a young age Apru trained as the flying city's apprentice aerotheurge before eventually becoming caught up in the tensions between those on the city who wished to remain isolated in their sky and those who sought to reestablish contact with those living on the ground. Throwing his support behind the rebels, Apru found himself on the opposite side of his teacher, who aligned with the aerolith's council in seeking to keep the city cloistered. Apru took part in the battle to attempt to seize control of the aerotheurge's chambers; after the master aerotheurge destroyed the locus of flight rather than allow the rebels to take it, Apru underwent a ritual to transfer his consciousness into one of the city's colossi, thereby preserving his knowledge of the highly restricted magical art.
After Nensa crashed in central Brightmarch, Apru left the city yet did not go far, making it only about ten miles before settling down in the marshes near the Ikena River. Addled and confused from the consciousness shift and his new form, he quickly fell prey to the same purposelessness that many colossi suffered following the retreat of their elven wards. Ultimately Apru would not rise from his resting place for roughly three thousand years, even as the river shifted its path and he became mostly covered by earth and silt.
In Y9976* a tribe of the Idrimi recruited a group of adventurers to search Nensa for the precept tablets and memory shards they believed to be held within, in hopes of finding the identity of Apru and encouraging him to walk again. The adventurers were successful in this endeavor and were able to find the elf-colossus' identity, memories, and precepts - presented with these, his recollections and motivation returned, and he agreed to accompany the Idrimi as a protector in their travels across Brightmarch.
Apru is thought to be the only surviving aerotheurge and therefore the only individual who knows the lost art. He is unwilling to share this knowledge with any, however, as even during his life as an elf he came to believe the aeroliths only served to isolate their inhabitants in an atmosphere of complacency and fear and therefore should not have been built.