| Marshall Sumner | |
 Colonel Sumner in 2379 | |
| Full name: | Marshall Sumner |
| Species: | Human |
| Gender: | Male |
| Homeworld: | Earth |
| Born: | 24th century |
| Died: | 2379 |
| Affiliation: | Federation, Starfleet Marine Corps, Atlantis Expedition |
| Family | |
| Marital Status: | Single |
| Career | |
| Occupation: | Starfleet marine officer |
| Final Assignment: | Commanding officer, Atlantis Expedition's military contingent |
| Rank: | Colonel |
| Insignia: |   
|
- "He carried the burden of a leader, and he carried it well."
- — John Sheppard
Colonel Marshall Sumner was a male Human who was a member of the Starfleet Marine Corps, and the first leader of the Atlantis Expedition's military contingent up until his death in 2379.
Biography[]
Background information[]
It is unknown if Sumner had any family who was still alive, and virtually nothing is known about his personal life. What is known was that he was very good friends with Colonel Dillon Everett.
2379[]
He objected to Major John Sheppard's inclusion in the Atlantis Expedition, stating that he disliked any officer who failed to follow the proper chain of command. Sumner led the reconnaissance team that made first contact with the Athosians. Though he allowed Sheppard to attempt to establish a rapport with them, he paid less attention to the people than to any potential technology or suitable evacuation site that might be found; this led him to disregard the Athosians' warning against exploring the ruins of an Ancient city there. Teyla Emmagan observed that Sumner "looks through me as if I were not there.". In short, his attitude was very similar to that of Jack O'Neil in 2359, seeing the eggheads as an obstacle to his operation, and a potential threat to his command and possibly his authority.
When the Wraith culled the Athosians, Sumner was captured along with some of the Athosians. When the Wraith came to collect an Athosian prisoner, Sumner attempted to offer himself to save the Athosian, but the Wraith refused the initial offer. After killing the Athosian, they returned to the cell and brought Sumner before the Wraith Keeper, who attempted to interrogate him about Earth. He refused to tell her the location of Earth, and, noting his surprising strength of will, the Keeper fed upon him, commenting that she had not tasted such strength in a very long time. Although Sheppard tried to rescue him, he did not arrive until Sumner appeared to have aged by several decades, with the Keeper still feeding on him.
When the Keeper proved resistant to phaser fire, Sheppard shot Sumner instead, believing it was what Sumner wanted him to do with Sumner later dying instantly as a result. This made Sumner the first ever Human casualty of the Federation-Wraith war. After returning to Starbase Atlantis, the authority rested onto Sheppard until it became official in 2380 by Stargate Command, and some persuasion by Weir.
Sumner's death would be a major source of contention between Sheppard and both Colonel Dillon Everett, who had considered Sumner a very good friend, and Colonel Steven Caldwell, although both eventually acknowledged that he had done so for the right reasons. For his part, Sheppard spoke highly of Sumner in a message back to Earth, saying he had borne the burden of a leader well and that in light of the looming Wraith assault, he wished Sumner was still with them.
Alternate reality[]
- In an alternate reality visited by SG-1, Sumner was the leader of most of the survivors of the Atlantis expedition when they chose to evacuate to Athos en masse after discovering the starbase's power problems, taking full official command of the expedition after Doctor Weir was killed by the Wraith. However, he and his men began experimenting with the Wraith enzyme as a means of improving their ability to oppose the Wraith, with the result that Major John Sheppard 'defected' to the Athosians with a select few expedition personnel as he recognized the danger of Sumner's approach. By the time SG-1 arrived on Athos from the 'prime' reality, the enzyme had rendered Sumner so paranoid that he was determined to hold on to his position, arguing that General O'Neill had no authority to give him orders as he technically wasn't part of Sumner's chain of command. Sumner was eventually killed in a later confrontation with the Wraith, while General O'Neill was able to negotiate a truce that would give the expedition time to return to Atlantis.
Alternate timeline[]
- In an alternate timeline, the expedition arrived discovering the starbase's power problems, where he discovered that the starbase would be destroyed. Sumner was one of many who died while attempting to leave the starbase.