Kazuradrop is one of the Sakura Five that didn’t make it into the game.
She is the Alter Ego of affection.
Unlike the other Alter Egos, she doesn’t hate humans. Conversely she actually questions the contradiction-filled actions of BB and the other Alter Egos. Kazuradrop is a gentle and quiet girl with a personality that values others over herself. She wants to return to being a complete AI, devoid of the errors that riddle the Alter Egos.
We designed her to be a nurse, so she is always neat and tidy. She is also very young and has absolutely zero combat ability. She is a specialized AI designed to work as a virus scanner. She would fix up or neutralize corrupted data or code that cause bugs. She is a health nut who loves to give her patients injections.
…Well, it’s easy to tell why she was cut after reading this far. She was too similar to Matou Sakura who works in the School Infirmary, so Kazuradrop was cut at a relatively early stage.
One of our ideas in the early games design phase was to have a village located in a dungeon where the various Sakuras would gather. Kazuradrop was supposed to live in that village.

Kazuradrop: “Welcome! This is a village where the more moderate-minded Sakura gather.”
Rin: “…Don’t you think this girl has gone way too far splitting up her ego?”
Kazuradrop: “If you return to us the Drops of the Sakura we originated from, we will give you items and heal you ♥”

Maybe things would’ve ended up like that.
Originally there was no Sakurament and instead there were “Sakura Drops” which were once part of the source Sakura. By gathering them and trading them for prescriptions from the School Infirmary Sakura you would be able to take back a share of the world and put it under your control. This was one of the methods of doing so.
Kazuradrop’s id_es skills are “Repulsion For One’s Kin” and “Insect Eater.”

Fate/EXTRA Material: Encyclopedia of Fate/EXTRA