Resident evil 5 Wesker's MADNESS kinda explained!!

[Rasko]

Well i passed re 4 one more time and then i saw he started being crazy even there here s video from end of Ada's mission!!

This gave me that what i missed in between RE4->RE5 or that is to say forgot now if you listen to him you l realise he got insane since he got Las Plagas

But still i don't believe we saw last of him 

[Albert Wesker]

yep bro I remember that, but he refers to Umbrella's re-establishment, and once that day will happen there will be significant changes in the world....I guess capcom forgot about that and let umbrella die forever...damn capcom 

they're such a disappointment in this last period you know, they f**k a thing after another everyday and really fast 

[William G Birkin]

yep bro I remember that, but he refers to Umbrella's re-establishment, and once that day will happen there will be significant changes in the world....I guess capcom forgot about that and let umbrella die forever...damn capcom 

they're such a disappointment in this last period you know, they f**k a thing after another everyday and really fast 

Well there was 5 years between him saying that and RE5. Things probably changed since then. He was presumed after jill knocked him out the window, so to keep his existence a secret, he probably wasn't able to re-establish Umbrella, and instead decided to take over an already existing company.