Mordin's Sacrifice - Mass Effect 3
Mordin is one of the most popular supporting characters from the Mass Effect series. As one of the creators of the genophage that sterilized the Krogan race, Mordin later feels that this choice was wrong, and sets out to cure the genophage. Although there are several outcomes depending on your choices, in this one Mordin prepares to deploy the cure, but sabotage threatens to thwart him. He ascends to the top of tower, leaving Shepard with the words, "Had to be me. Someone else might have gotten it wrong." We last see Mordin singing his Gilbert & Sullivan tunes as the tower explodes. It's a fitting end to his arc, and a powerful, yet saddening, moment for gamers.