It looks like ascension doesn't really turn the person into a being of greatness, but instead just empowers them and push them further at their personality? like how nasus gain more wit and renekton become more brutal after the ascension?
Power corrupts, absolute power corrupts absolutely.
Basically, I think it's just much easier to have the darker sides of your personality shine through if you have the capability to do so. So like for Renekton, "Sure, we could negotiate a surrender...but now I'm a giant crocodile man and it would be WAY faster to just turn you into a splotch in the sand."
Its still good, they worship the ascended regardless of their attributes. It is just an after affect. the ascension pushed Azir and Nasus to greater heights and will. While Xerath and Renekton became warped and corrupted. Though Renekton only became so infamous after Xerath poisened his mind.
You also gain the ability to not age too soon, meaning you can live about 10 lifetimes.
Pretty much just turns you into a semi-mortal being and in some cases, into an animal fitting of your personality.
