A Custom Lightsaber is one constructed to reflect the personality of its owner. What makes it 'custom' is that it is not a stock DJB graphic created by the Lightsaber Creation Tool.
Ownership
A specially-modified lightsaber may only be carried by a Sith Battlemaster, Obelisk Prelate, or Krath Archpriest . If you are this rank or higher the custom weapon will be displayed on your dossier after approval by the Herald.
The implementation and usage of Custom dual sabers (two single custom lightsabers) is available to Sith Warlord, Obelisk Primarch, or Krath Pontifex.
The Custom double-bladed lightsaber may only be carried by a Dark Side Adept or higher.
Custom lightsabers must be sent to the Herald for evaluation.
Creation
Anyone can construct the image for a custom lightsaber.
Trivia
Custom Lightsaber (samples)