May is a new intelligence agent born in Asia, she has high battle capabilities. Her identity is kept as a secret even within the organization; she has disguised herself and infiltrated into Counter-Terrorist camp near the border and her first mission was to observe her colleague who is under solo activity.
Even though the max attack power is 25, it takes a very long journey to get that because the early level ups focus on HP first , and then followed by the others. Even after reaching level 50, the attack power is only upgraded to level 7. It requires nearly level 90 to upgrade the attack power to its maximum. Therefore, it is recommended to use powerful weapons during earlier levels since it's hard to kill zombies later on with a low attack power.