During the mid-23rd century, an alien race of unknown origin traversed through known space, attacking selected targets to test their defenses to ascertain whether or not they were worth conquest. To achieve this, the species sent out scout fleets that located and attacked potential targets, such as the Gaim or Babylon 5. The survival of such fleets against potential targets is what decided whether or not they were worth the resources to conquer, making it necessary for the targets to destroy most, if not all, of the fleet.
In 2262, this species attacked Babylon 5 after encountering the Gaim sometime before, the latter being able to warn Babylon 5 in advance of the scout fleet's arrival. Ships belonging to this species destroyed long-range probes sent out into hyperspace by Babylon 5. Afterward, an initial wave of ships traveled through the jumpgate and attacked Babylon 5 and the launched Starfuries were destroyed in combat. Later, the species arrived with their main fleet, attacking the station with cruisers and fighters which were able to damage B5's hull with a few hits. Breaching pods allowed soldiers wearing suits of armor that covered their entire bodies to penetrate and attack the station's lower levels. All invading ships were eventually destroyed. 
|Arnassian • Caretakers • Delgashi • Divloda • Enphili • Faranian • Fen • Golian • Hive Mind Bacteria • Kaitay • Kinbotal • Kulan's race • Kurlin • Lorkan • Lumati • Merla • Mind-altering aliens • Mipasian • Moradi • N'Grath's Race • Na'ka'leen • Nimue • Norsai • Orion • Ralgan • Riar • Scout fleet race • Servitors • Sh'lassen • Shoggren • Soom • Soul Hunter • Streib • Tak'cha • Tikar • Tokati • Tzillari • Vindrizi • Vinzini • Visitors • Wychad|
|Shadow Servant Races|
|Keeper • Shadow Surgeons • Sleeper • Soldier of Darkness • Wurt|
|Extinct and Nearly-Extinct Races|
|Belan's race • Ceti • Daltron • Dureena's race • Ikarran • Original Lorkan • Taratimude • Varn's Race • Xon|
|Alacan • Cauralline • Cthulhin • Deneth • Froon • Krish • Mitoc • Morellian • Thrantallil • Throxtil • T'llin • Tuchanq • Ylinn|