Need help on this

There a anime i watched around 2012-2015 about a squad wearing red suit slay monster or zombie. There a guy in a van that observe and help the team. A girl who use motorcycle similar to akira but have special symbol on the tire to kill the monster. Mc use dual hand gun. Thing start to fuckup when the guy in the van got ambush by some kind of star fish that stick on his face and kill him. The squad starting to die one by one until there only the mc and the girl left. The mc pull the girl to hide and reload his gun. When he turn back the girl head was already chop off. In the end there a girl in a highschool uniform holding a sword looking at the mc. Please help me with this one. I been surfing through myanimelist but found no results. Thk guys