Seneca Crane was the head Gamemaker in The Hunger Games. He was in charge of running the 72nd, 73rd, and 74th Hunger Games and ordering obstacles into the arena. After the 74th, when he allowed the games to end with two victors, he was killed under the orders of President Snow.
The Hunger Games
Throughout the film, Crane met with President Snow in the latter's rose garden to discuss the rising popularity of Katniss Everdeen with the Panem television audience and Snow's need to keep her (and the districts) in line. After a meeting with Haymitch Abernathy led to Crane's initial change in ruling to allow two victors, Snow discussed the implications of the change with Crane and expressed his opposition to the change.
Despite Snow's opposition, Crane decided to allow the two victors to live after they threatened to consume the poisonous nightlock berries and leave the Games with no victor. In the book it is never revealed how Crane died, only that his execution was ordered by Snow. In the film, Snow has Peacekeepers escort Crane to a room containing only a bowl of deadly nightlock berries, locking him in. Some say that he ate some of the nightlock, some suggested that he may have broken the glass and fallen to his death, or starved himself. However, in The Hunger Games: Catching Fire, Plutarch Heavensbee and Katniss Everdeen talked about Crane choosing to "quit breathing," implying he may have hanged himself instead. Katniss hanged a dummy, painted to represent Crane, during her private session for the 75th Hunger Games.
As a result of not following procedure, Seneca inadvertently paved the way for the rebellion that began in Catching Fire. Had he opted to kill both Katniss and Peeta, the idea of the rebellion would have died along with the two tributes. However, his granting mercy and victory to the two backfired tremendously as the Districts saw this as an underlying hint that the Capitol, despite their harsh treatment of the Districts, could be merciful, a feat President Snow was not fond of. Furthermore, Seneca ruined the tradition of the Hunger Games--a reminder to the Districts that everything could be much worse if the Capitol were allowed to execute District citizens at random. His actions would once again be repeated by Plutarch Heavensbee in Catching Fire, who effectively collapsed the tradition of the Hunger Games when he secretly devised a rebel plan to rescue Katniss from the Arena.
Seneca is first mentioned when President Snow reveals that he had to execute Crane for not killing Katniss and Peeta when he had the chance.
Much later, when Katniss is trying to find some way to rebel against the Gamemakers, she grabs a dummy and ties a noose around its neck, writing the name SENECA CRANE across it. The Gamemakers are shocked and horrified with her performance, and quickly dismiss her.
After Katniss tells Effie Trinket, Haymitch, and Peeta about her performance in front of the Gamemakers, Effie says, "Oh Katniss, how do you even know about that?" meaning that she knows what happened, and that he was most likely hanged.
Seneca Crane was a middle-aged Capitol citizen, with light skin and light blueish-gray eyes. In the film, he sports a uniquely styled beard, shaved in an intricate design. He has dark, short hair, and has applied gel to the back.
Despite being the head Gamemaker in the Hunger Games, and the pleasure he showed in the dangers of the arena (such as his delight in seeing the mutations that were created from the dead tributes) as well as watching people die, Seneca Crane was not entirely evil and showed a degree of mercy by allowing both Katniss Everdeen and Peeta Mellark to survive the Hunger Games. His sentimental streak ultimately got him executed. He seemed uncomfortable around President Snow, and did not fully agree with the way Snow ruled Panem, but it wasn't until Katniss brought out the berries that would kill both her and Peeta that he finally decided not to go along with everything Snow said.