Ah hell, I'm too far behind to really go in depth in John's adventures in a timely manner. I'll try to do a quick summary.
In ME1, John had no problem with serving out revenge. He shot Dr. Saleon himself before Garrus could get a shot off, and Jeong also ate a bullet. But when John came across Corporal Toombs, his fellow squadmate from Akuze, and allowed him to kill that scientist, Toombs went ahead and killed himself afterwards. This did not sit well with John, and he spent a long time thinking about it. He finally came to the conclusion that Toombs was filled with pain and sorrow, and revenge became his only outlet. He was a shell of his former self, and John did not want to go that route. This affected his encounter with Balak. He couldn't let Balak go because he was too dangerous, and the deaths of Kate and her assistant weight heavily on him for a while afterwards. But he stayed his hand when he finally had Balak on his knees, and let the Alliance officials take him in so they could interrogate him and possibly prevent another attack.
When John took Jack to Pragia, he saw that they had some things in common. She may have had a more troubled past, but she, just like him, was trapped in her past. He convinced her to spare Aresh so she could finally let go, and he also gained a new respect for her.
He than went towards Tuchanka to help Mordin on a personal matter. He caught up with Wrex in the process(he was really glad he stayed his hand on Virmire too). When they finally got to the hospital and met the Weryloc "spokesman", John tried to reason with him first(what a fruitless waste of time). John moved on to intimidation to no avail, and the spokesman started to go off on some egotistical rant. John stopped him midway and turned him into a flaming pile of cinders. Later on, John and co. came across the Krogan scout. The scout was sick and delusional, and John kicked his a**(figuratively speaking) to motivate him. After killing Guld and his thugs, they finally ran into Maelon. Like Mordin, he was filled with guilt over the Genophage Modification Project, and became reckless and wasteful in his experiments. He also became a liability. However, John kept Mordin from killing him. Not because he cared about Maelon's well-being(in fact, he wanted to put a bullet in Maelon himself), but because Mordin was already guilt-racked to begin with, and killing Maelon would probably add to it. Besides, Maelon was a wash-up, a has-been. After Mordin had STG terminate Maelon's clearance to the Genophage Modification Data, he would have no chance to restart his experiments. Any other Krogan clan would probably kill him on sight too.
While John was on Tuchanka, he helped Grunt deal with his "puberty" problem. He also enjoyed putting Uvenk in his place, both before the ritual and after(Grunt's answer to his proposition came at muzzle velocity). As Wrex put it before, John did "a favor to the Universe."
Finally, he decided to head toward Illium to help Miranda with her problem, and to recruit the assassin and justicar. Before he could, Garrus needed to speak with him. Garrus finally got some intel concerning Sidonis, and wanted Shepard's help so he could get his revenge. This troubled John, because he didn't want Garrus to go down the same path as him, and he told Garrus that the mission came first. He would help Garrus when they had time.
On Illium, John ran into Gianna Parasini and helped her bring an Asari down a few pegs. He also met up with Liara. It appeared she had lost her innocent naivette, and this also troubled John(like Tali, she reminded him of his childhood friend). She did however ask for his help, and he initially obliged by hacking some terminals for her. Yet when he found out that she needed the information from these terminals to exact revenge on the Shadow broker, he told her that she had become obsessed. She initially told him off, but stopped herself midway. John caught a glimpse of her former self, but couldn't stand to see her this way. After getting the whereabouts of Thane and Samara, he left her office and went towards the nearest bar.
Once in the bar, instead of having a drink, he saw Conrad Verner. Conrad was making a fool of himself, and John vented some of his frustrations on Conrad to knock some sense into him. Apparently, Conrad got conned by an arms dealer, and John told him that he would take care of it. Still in a foul mood, he vented his remaining frustrations on the Arms dealer and scared her s***less. She also agreed to tell Conrad that he did a good job and to move on.
Once Conrad thanked John for his help, John proceeded to drink and had a nice chat with the bartender(I'm Commander Shepard, and this is my favorite bar in the galaxy). Afterwards, he came across Shiala and helped her with some contract issues. Now he's headed off to recruit Thane.
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Retour en haut
]. I have done Horizon, gotten all my squad [minus Legion] and am doing some of the loyalty missions. I think I am one mission away from having to do the Collector Ship. Luckily, with the help of Gibbed, it will be a cake walk [I know it helps because that is how I was able to get through that Collector Ship mission and get the Insanity trophy on the PS3 version].
. Instead of a battlesong, Grunt promised he'd sing "The Krogan Queen" in your honor. 
