Darth Achelon, a Sith Lord in the Sith Empire, was a male Human who answered to Darth Thanaton of the Dark Council. Moff Pyron noticed a chance to evaluate the Silencer superweapon by using it against a naval force. Lord Kallig, Thanaton's rival, was eager to testing the Silencer so he could gain an alliance with Moffs against Thanaton, and had to make a choice of whether or not to rescue Achelon.
The destiny of Achelon can go in three different directions. Kallig has the option of allowing the Republic to destroy Achelon's ship, using the Silencer on him, or commanding him to retreat. If Kallig tells Achelon to retreat to a safe distance before the Silencer is activated, Achelon will promise not to attack Kallig without warning. Later, Achelon is seen on Corellia, under orders from Thanaton to assassinate the player. However, Achelon declined to attack Kallig, as he had been spared by him. After Kallig defeats Thanaton and takes his seat on the Dark Council, Achelon is among those who pledge allegiance to the new Dark Lord. At this point, you can give him instructions regarding your assets. If Achelon is deceased, Lord Kirnon will fill his role.
If Achelon met his end, Thanaton will command Darth Kallous to assassinate Lord Kallig.