Battle Style
Warning - This page is pretty graphic. I think the battle and death scenes are what make Parasyte a seinen manga and not a shounen one.
Reiko had to fight other parasites only once, but it was an epic battle. Kusano felt like Reiko had changed too much mentally and emotionally, and decided to kill her because he perceived her as a threat. He got two other parasites to help him kill her, probably to ensure that she would die. What they didn't count on was her unique way of fighting. She not only lived, but took out all three parasites on her own.
Reiko sensed them on a walk home like they knew she would. Kusano told her that they didn't bother hiding because of that fact. One of the parasites asked her why she didn't run.
I was intrigued. Curiosity defeated me.
Reiko told them that hostility and blood-lust were two of the strongest signals parasites emit. She used that later in defeating them. She also told them that she was pleased with what they were doing, as it proved that parasites were becoming more different and more unique. Then she said goodbye. As the parasites moved in on her, she said one of my favorite quotes in the series.
Did you think just the three of you could do this?
Usually, when parasites battle, their faces distort into blades. The bodies stand there, and the blades extend and fight. If Reiko had fought in this way, she probably would have definitely lost as she was outnumbered. What she did instead, though, was use her blades to push her body up and away from the parasites, and then she ran. By running, she was able to unorganized their attack and separate the parasites so that she wouldn't have to handle all three at once.
She was wearing heels, so she wasn't able to run that long. She eventually had to stop running and battle one of the parasites. She began the one-on-one battle like normal parasites. She moved incredibly slow, though, allowing the other parasite to cut off part of her blades.
Go ahead. Take it.
The dismembered blade entered the other parasite's body while he stood watching, confused. Reiko used the opportunity to take off running.
Kusano couldn't comprehend what Reiko was doing. It made no sense to him.
She split in two? Half a parasite won't be able to control the body for long. This is suicide. Tamura Reiko was far too intelligent to end it like this!
The half of Reiko inside the parasite fought from the inside and took control of his lower body. It used his body to push the other parasite helping Kusano down. Then it pushed its way out into the other parasite, finishing off the first.
Kusano saw what was happening, but misinterpreted it entirely.
I get it now. Inside another body, you might survive.
I guess Kusano decided to kill the other parasite to make sure that none of Reiko survived. The part of Reiko inside the parasite made her legs start walking forward, making Kusano see her as a threat even more. Kusano and the other parasite fought. Kusano cut her up.
The body you were stealing is now in pieces!
While Kusano was yelling at the half of Reiko inside the other parasite's body, the rest of Reiko used the opportunity to kill Kusano from behind, cutting off his head.
Like I said before, hostility and blood-lust are the strongest waves we emit. And this gives us extremely important information about other parasites outside our range of vision.
She told him that he cut up his ally's body sensing the powerful hostility near him. She was probably sending those from inside the parasite's body to keep Kusano fighting. The scraps of flesh all over camouflaged the other half's approach. They reconnected while Kusano began to die.