In video games stories, violence is motivated by greed, family, survival and yes, religion.
In the fictional world of Mass Effect 2, the assassin strikes with both grace and extraordinary violence. He takes out the two guards and then kills his target. When she's dead he leans over her body, crosses her arms and begins to pray.
The classic scene illustrates the deep, spiritual element of the assassin Thane and also shows extraordinary violence.
Shepherd: "Can we talk? I came a long way to talk to you."
Thane: "One moment. Prayers for the wicked must not be forsaken."
Shepherd: "Why? Do you really think she deserves it?"
Thane: "Not for her. For me."
The character Thane is an assassin who follows the religion of the drell. This is an interesting case because his religion doesn't "inform" the violence, although it allows for it. His religion basically says that the body and soul are separate. So his body can be used as a tool by someone else, and assassinations aren't anything he bears guilt for -- the person who hired him bears the guilt. But Thane still feels guilty. He thinks about his victims, he prays for his victims. So is the religion violent here? Not necessarily, although it allows for the violence he commits, and must commit, in order to save the galaxy. The scene here depicts Thane killing a target, and then praying.
The antagonist is called Gareth Dysley. He's a "Primarch," which when you translate it means "Great Pope." Dysley's role in the society of the game is similar to that of a Pope. He's a mediating force between their god and humanity. He oversees their religious traditions, at one point the player even sees people walking around in what look like habits. His own dress resembles that of a Pope from the Middle Ages. And yet, he's the antagonistic force who wants to destroy/enslave humanity. This scene depicts a confrontation between the protagonist party and Dysley.
(Start at 6:33) The Castlevania series itself has a clear-cut religious connotation. Here we have a video game series that draws on the essentially Christian literature of vampires. In the classic novel "Dracula," vampirism was seen as a sort of demon possession, which could only be hurt through the use of a cross, holy water, recitation of biblical passages and the use of a "wooden stake" (an allusion to the nails in the crucifixion). Castlevania is planted in that literature and our main character Gabriel plays a sort of "holy knight" out to destroy the demons ravaging an eastern European countryside. And yet to do it, Gabriel must deal death. In the scene here, Gabriel and Zobek are discussing an abbot. Judging from where this game takes place, the abbot should be Eastern Orthodox and thus called a Hegumen but since he's called an "abbot" we have to assume the abbot is Catholic. He's a bad man, keeping the villagers in harm's way. And he's clearly a symbol of organized religion. But so are Gabriel and Zobek and yet they're violent characters.
(Start at 6:55) This game could be seen as the game most critical of religion that was featured in this study. The game revolves around the search for something called the Piece of Eden. It allows the holder to control people's minds. The argument is that the parting of the Red Sea, the turning of water into wine, the Resurrection -- all of it was courtesy of Church leaders who used the Piece of Eden to convince people that a miracle occurred. The Templars, who appear to be exactly what they're called, want it so they can use it to control the people. The Assassins, who are depicted as Enlightenment-era secularists, want to keep it from them. As it turns out in the end, the Assassins don't have good intentions with this thing either. This scene depicts a confrontation between the protagonist Altair and Al Mualim, an assassin who has taken possession of the Piece of Eden. Al Mualim, in classic bad-guy fashion, is describing his evil plot to the captured hero.
(Start at 3:20) There are a lot of depictions to talk about but since so many of these games focused on the Templar knights, think about the Knights of the Nine. Again in dress, manner and mission there are similarities to crusader knights. There's this idea that the Knights of the Nine must be pure, holy. "The Nine" is a reference to the Nine deities of Cyrodill; deities that serve a similar role in the organized religion of Oblivion to God in the Christian worldview. The same sorts of debates about holy knights raised with Castlevania also applies here. The Knights of the Nine are holy knights, but to accomplish good, they must kill a lot of bad guys. In the scene here, the hero has killed the spirit that has kept the original Knights of the Nine trapped in this world as spirits. He begins conversation with the spirit of a knight who describes his soul as being "freed" and reminisces about his fall from grace during life.