Brother, you had to be so arrogant
--Alex to Albert after his death.
Born Alexander J. Wesker.The younger brother of Albert and Henry Wesker, not to mention the youngest of the Weskers. Intelligent, manipulative and cunning, he, being the youngest, was always underestimated by those older than him, especially Henry. Albert was always the one closest to him. Unlike Albert, he doesn't have a dark persona or a cold attitude, he possesses a heart and would sacrifice himself to save anyone he cares about. This attitude is the reason he's popular in school and is respected by his classmates. But this attitude shadows his vengeful and often explosive self. He has yet to reveal his true intentions.
After graduating, he immediately joined the Umbrella Corporation and researched on one singular parasite for several years - the Insanity Parasite. He became obsessed on improving it, but failed time and time again. But this did not stop him from injecting a specialized version of the virus - the Insanity 84. This version differs from the previous one because it doesn't drive the host insane. Other enhancements from the previous are replaced by slightly more humane transformations like claws from hands. The 84 also improves the hosts' metabolism by recovering from gunshots at an extremely fast rate and other abilities are ampified to maximum.
Proud with his creation, he shows it to Albert who is proud of his little brother. However, Henry is not impressed. So, he develops a rage against Alex and because he and Albert are nuisances in Henry's plan; he decides to destroy them in an airfield outside of New York. Alex is knocked unconcious early in the fight, Albert continues solo for a few minutes. Alex eventually awakens and finishes off Henry.
A few years after the fight he receives a letter stating that he has a plan to destroy the humans. Alex isn't in anyway concerned. Albert goes through with his plan which fails, Alex, from an AC-130, watches his brother's downfall.
Now, with his brother and father (Spencer) gone, his attitude would take a drastic and destructive turn.He then creates a plan to spread his brother's Uroboros and his Insanity 84.However, there are many nuisances in his plan.Both the BSAA and the US government would attempt to stop him.This plan takes years to take shape, he successfully creates a virus out of the two parasites, but doesn't name it.
Isaac, stop this, you can't succeed
No, I need to stop you
--Isaac and Alex trying to talk each other out of a fight
He partners with Isaac Mercer, an old friend.Mercer assists Alex throughout the plan, but doesn't know what the real plan is.Mercer soon knows of Alex's real plan, this angers him.Mercer talks with Alex, trying to convince him to not go through with the plan.Alex soon finds his old friend turning into a nuisance in his plan and plans to assasinate his old friend.Mercer hears about this and in a last ditch attempt to save himself.So, he uses a machine to activate his own version of the virus (he doesn't name this).This machine gives him superhuman abilites, such as being able to control bolts of electricity.They were friends no longer.
They try to talk each other out of a fight but fail.So they fight in the same spot where Alex killed Henry years prior.Their fight is bloody, merciless and relentless.Eventually, their powers give out.They both fall to the ground.They both die in the airfield.Then suddenly, Alex's hand starts to move.Alex stands and looks at the dead body of his old best friend.His last words to his friend were I told you, you can't succeed.