She was friends with Shinji's mother.
She was involved in the first contact experiment.
She was one of the first ever Eva test pilots.
Basically Mari was written in as the lynch pin that holds the entire shitheap together, and does so by bringing in even more fan service. She doubly makes both Asuka and Rei fags eternally butthurt since she is best girl.
Marie is the key to all of this... if we get Marie working.
Because she's a funnier character than we've ever had in the series before.
To replace a Toji as the other Eva pilot
To replace Kensuke as Glasses-kun
To replace Kaji as the adult that's partially outside of Nerv
Take all the side characters and condense into one
And while we're borrowing plot elements from spinoffs to make Rebuild, might as well throw in those one-shot girls into Mari's design
This desu senpai.
Her point is having the hottest damn plugsuit ever designed but only wearing it once for some stupid fucking reason.
To be mai waifu and best Rebuild girl.