Ends of the Earth
Yat-Yat-Uzrio was given to Nikola Tesla in 1889, when he first began experimenting with the idea of wireless electricity.
The Society for the Advancement of Lesser Races created the imp expressly for Tesla, which was of note as the Society had largely ceased imp production some 7 or 8 centuries prior. Given that all imps are immortal, there was no need for a surplus after the first few thousand or so. It should be noted, however, that though all imps are physically immortal, the data housed within them is not, and is lost to the ether unless backed up to another imp.
Tesla made great use of Yat-Yat, as history informs us, until his rather untimely death due to “coronary thrombosis”. There is no evidence to support any foul play in his death, but there are a variety of scholars in the SALR that have remarked upon the coincidental time of his death so soon before he was to unveil his latest project (the nature of which has not been revealed by the Society). Presumably, any future owner of Yat-Yat would be able to discern what the project was, but everyone who has used the imp after Tesla has found him remarkably uncooperative and occasionally even directly disruptive.
Organic Hard Drive
Loyal Past the Grave