Dark Lugiel is the wielder of the Dark Spark and the main antagonist of Ultraman Ginga and Ultraman Ginga S.
Shin Ultraman Retsuden 79
Ultraman Ginga and Dark Lugiel were originally one entity, but their conflicting views on how to create an "ultimate paradise" led to them splitting. Dark Lugiel believed that all lifeforms must be paused, while Ginga thought that active lifeforms brought prosperity.
After becoming two separate entities, Ginga inherited the light while Dark Lugiel gained the darkness.
During the Dark Spark War, Dark Lugiel used the Dark Spark to transform every Ultra and Monster into a Spark Doll. However, Dark Lugiel and his light counterpart Ginga also wound up as Spark Dolls, with Lugiel being locked in his Spark Device.
Lugiel then sent his minion, Alien Valky, to distribute Spark Dolls.
Dark Lugiel was eventually revealed to have been inhabiting the body of Furoboshi Private Elementary School. He was later purged from her body by Hotsuma Raido, but this didn't stop him from reviving himself.
Ultraman Ginga then went to challenge Dark Lugiel, but his dark half managed to overpower him. However, Ultraman Taro managed to regain his full size and went to fight Dark Lugiel. Dark Lugiel managed to defeat him too, but not before he could revive Ultraman Ginga.
Ginga and Dark Lugiel then clashed again. Ginga eventually defeated Lugiel with a Ginga Especially, freeing all of his Spark Dolls.
Ultraman Ginga S
Dark Lugiel's body was later recovered by Exceller, who sought to combine with it to create a powerful being. Dark Lugiel was eventually revived thanks to the Victorium Crystals. Lugiel's first move after his revival was to combine with the Live Base on Earth, taking the Victorium Cannon and becoming Vict Lugiel. While Vict Lugiel was initially piloted by Exceller, Dark Lugiel eventually revealed himself and killed Exceller by transforming him into a Spark Doll.
After his revival, Dark Lugiel resumed his plan to petrify all life. He was combatted by Ginga and Victory, but managed to have the upper hand in the fight. This changed when Zero hacked and weakened Vict Lugiel, allowing the Ultras to gain the advantage. Lugiel was eventually finished off by the Ultra duo with a Cosmo Miracle Especially.
Ultraman Ginga S Movie Showdown! The 10 Ultra Warriors!
An Eteldummy copy of Dark Lugiel was created by Etelgar. It was defeated by Ultraman Ginga Victory with the Ginga Victory Breaker.