Technically, the Silencer is merely a cannon attachment for a Harrower-class Dreadnaught. The ship itself is the Doombringer. The Codex entry for the Silencer confirms it to have been developed by Darth Mekhis and the Silencer is mentioned as being part of the Sun Razer project in the Lost Suns comic. The prototype was left unfinished after Mekhis got killed and funds were cut by Thanaton because he thought it was an unnecessary weapon and then Moff Pyron had the Inquisitor get the necessary component to make it operational.
Thanaton only became a council member when the Sith Inquisitor was on Belsavis, and he was in charge of ancient knowledge, I guess technology should be handled by Darth Hadra.