The droid Viscount Tardi was designed to replace the Human Tardi who had died more than a month before the Rebel Alliance had intended to have him conduct a financial transaction for them. The Rebels decided to secretly replace Tardi with a droid to help Princess Leia Organa negotiate the sale of T-65 X-wing starfighter at the Bank of Aargau due to Tardi's impeccable reputation with the bank.
They arrived on Aargau without problem since there was little in the way of security checks done on inbound travelers. However, since everyone leaving the planet had to go through scanners in order to prevent theft of Aargau's precious metals, Leia had to find a way to avoid having the droid detected since if the ruse were found out, the transaction would be voided. She accomplished this by luring Darth Vader into attacking the droid, "killing" him during their visit.
- Star Wars 48: The Third Law (First appearance)