What do Vader and Sidious have in common?

[anti_cyclone]

A few more suggestions:

Darth Scrutable
Darth Stant
Darth Corrigible
Darth Valid
Darth Cantation
Darth Anity
Darth Cluded
Darth Sipid
Darth Clined
Darth Different
Darth Dent
Darth Fra-Red
Darth Terior