Sakura

A big busty girl who is very close to her Professor. She often acts more as an assistant and sometimes bodyguard to him.

It was shown in a chapter that Sakura was from a group a genetically engineered humans that were trained for killing until she met Itsuki. In one chapter it shows off her strength when she unarms a man armed with a gun and in another she even makes a hole in a solid wall and even takes down a man twice her size in a single strike.