Developed by: BioWare
The Mass Effect franchise is one of the best examples of how much a player can care about fictional characters and the last installment of the trilogy is the perfect embodiment of this assertion.
Through its dialogue branches and morality system, players spend three games developing deep bonds with their favorite characters and sometimes, even diving into romantic relationships with them.
In the game that marked the finale of the fight of Commander Shepard against the threat of the Reapers, an ancient race that aimed to harvest organic forms of life, players continued to develop bonds with the characters, but it all lasted until the very last mission.
I will not go into detail, in order to keep myself from giving away spoilers, but the fate of your beloved squad during the final push against the reapers will depend on the choices made during the game.
I must admit that my squad fell on the battlefield in my playthrough and seeing them dead, because of my actions, after three games of bonding sent me into one of the toughest guilt trips I have ever underwent.
One of the best example of how games can create guilt in a player. Needless to say, I dropped many tears.