Jack Krauser is one of the main characters in the Resident Evil: Darkside Chronicles game. He is a soldier assigned as Leon S Kennedy's partner to apprehend the drug lord Javier Hidalgo.
The story starts off with Leon S Kennedy and Jack Krauser entering a village in order to meet their guide. They noticed that the streets are empty and no people are present in site. They also overhear a news report about over 50 young women going missing. A villager begins to approach Krauser, but due to Leon's experience in bio-terrorist attacks; Leon knows something is not right with the guy. Once Leon makes that observation the man tries to attack and the zombie survival ensues. A swarm of T-Virus infected villagers tries and attack the duo as they fight their way to the guide. Unfortunately when they reach the meeting spot the guide is badly injured and on the verge of death. Before the guide dies he informs the two that a girl fled from Javier's mansion and is the cause of this disaster that has befallen the village.
Leon and Krauser heads to the church in order to find a boat. They come across the only lying person in the village, Manuela Hidalgo. Manuela is singing to this large sea-creature like B.O.W, as soon as she stops singing the two are attacked by the B.O.W. The duo manages to defeat the monster and sends it fleeing from the scene.
Leon and Krauser asks for Manuela's assistance in taking them to Javier's mansion who escaped from there earlier. Manuela agrees, and they are meet with Javier Hidalgo when they reach the dam. At this time Javier informs the two that not only is Manuela his daughter but that she is the carrier of the T-Veronica Virus. The two are baffled by the information and are soon sucked into the dams waterway. manuela jumps in after them in order to escape her father.
Soon after Leon reveals that he was under special orders from the president of the United States to eradicate all existence of the T-Veronica Virus. Krauser agrees to assist Leon in his mission and the two meet up with Manuela. At the mansion, it is revealed that Manuela needs fresh organs on a regular basis in order to survive the T-Veronica Virus (Informing the duo of the fact that Javier is the reason for the missing women). This is the reason why Manuela escaped from the mansion. Upon his daughter's escape Javier injects her doctor and his personal army with the T-Virus as punishment. He also injects himself with the T-Veronica Virus. Prier to the showdown with Javier, Krauser is shot with a spear-like tentacle from the large sea creature B.O.W.
Javier mutates into this huge monster after exposing himself to the T-Veronica Virus. Manuela assists Leon and Krauser in defeating her father with her powers gained from the virus. After defeating Javier the duo is flown back to the US(According to the players actions Manuela may live or die at the ending).
After this Krauser is taken out of the army due to his injuries to his arm. He then fakes his death and joins Wesker's organization.
Resident Evil 4
In Resident Evil 4 Krauser is infected with the Master Breed of Las Plagas. When you first see Krauser he is given orders by Osmund Saddler to kill Leon S Kennedy. Krauser is secretly present in order to infiltrate Saddler's organization (the Los Illuminados) to get a sample of the Master Plaga sample for his employer, Albert Wesker. Krauser is working with Ada Wong, but due to his lack of trust for her they don't particularly get along. Krauser fails to kill Leon when Ada saves him from being stabbed by Krauser's knife. This only raises Krausers suspicion about Ada being untrustworthy and will eventually betray Wesker.
The next time you come across Krauser, he tries to ambush Leon and a gun fight soon ensues between the two. The two find themselves in a tower and Krauser mutates his left arm into a blade and shield. Leon manages to defeat Krauser and escape before Krauser's laid explosives blow up.
Krauser appears once again at the end of Assignment Ada as the final boss. The two are on a bridge fighting. Again Krauser has his blade like arm at the ready. At the end of the mini game "Separate Ways", Ada and Krauser fights once again. Krauser is badly injured from the explosion but lives. Ada defeats and kills Krauser.
Krauser is only available in mercenaries after you receive a 4 star level on Salazar's Castle level. Krauser starts off with a few flash grenades and a first aid spray. His default weapons include a bow and arrow (which has as much power as a shot gun but is hard to aim with) and his knife. You can actually use Krauser's mutated arm, which is the best part about using him in mercenaries. After killing a certain number of enemies his arm will glow red allowing him to fully mutate. You can only make a straight dash from Krauser's starting location but you manage to kill any enemy in the path of the dash. This is very helpful when going against the stage bosses.