
"Horrific as it may sound, there are two of them now." = Space Pirate log from Metroid Prime 2: Echoes.
Dark Samus (ダークサムス Dāku Samusu) was a being of Phazon taking on the form of Samus Aran and the reincarnation of the organism known as the Metroid Prime. After making a cameo appearance in the secret ending of the Metroid Prime game, she[1] became the secondary antagonist and the final boss in Metroid Prime 2: Echoes, and the main antagonist of Metroid Prime 3: Corruption.
Personality[]
Dark Samus, as her name implies, was shown to be cold, calculating, and utterly merciless. The lives of her opponents held little to no value to her. When necessary, she used her allies to her own gain. A prominent example of this was seen in her use of the corrupted Rundas, Ghor, and Gandrayda to battle Samus, only to kill them and absorb their powers after each hunter was defeated. The extent of her cruelty is described in one of the Pirate Logs, where she is said to have ordered her Pirate forces to jettison the surviving crew members of the G.F.S. Valhalla raid into space.


Dark Samus demonstrated compassion only once in her entire lifetime, and only to Metroids. This was implied in Echoes, where a Space Pirate log states she was attempting to free captive Metroids that were being researched in Agon Wastes, leading the author to conclude she was responsible for the recent disappearance of specimens. The cause for her actions were likely due to her origins as the Metroid Prime.
Dark Samus was also insatiably gluttinous for Phazon, likely a remnant of her origins as Metroid Prime. Throughout the series, absorbing Phazon was a recurring goal for her. She would kill anyone in her way, as the Space Pirate Logs in Echoes mention that Dark Samus killed any Pirates that impeded her quest for Phazon, but otherwise ignored them. Similarly, she would also kill any Darklings that happened to be in her way, as evidenced by her actions immediately prior to confronting Samus a second time at the Sanctuary Fortress, where she slaughtered a couple of Dark Pirate Troopers before proceeding to absorb the Phazon containers they were guarding.
Her personality underwent a great change between Echoes and Corruption. In Echoes, she was portrayed as unstable and unpredictable, shown by her maniacal laughter and chaotic attack patterns. By the time of Corruption, she was significantly calmer. She was also shown to be quite cunning, capable of long-range planning, and remained collected even if her plans were not going accordingly - the massive invasion she led on Norion would have succeeded, if not for Samus Aran. It is possible that her absorption of Phazon on Phaaze was sufficient to stabilize her physical form to a certain extent, allowing her to focus on other tasks besides her hunger for the mutagenic substance.