Custom battle system issues

i have a custom battle system that pretty much works except for 1 thing... i cant kill the first enemy in the game. i had tested the fight and i fought for a long time and he never died. i could be killed and i had 1200 hp while he had 2500 hp. i even did more damage then him there was a healing chest so i could heal so i would still live. but no matter how long i fought he wouldn't die. for the battle system i make a map with my enemies. for Skar there are two parallel process events next to him for his attacks. the attacks do deal damage to me. when i press space near him its supposed to show my attack animation then his hp variable goes down 30. he just seems to never get hurt though. can someone help me?

i dont need help anymore i figured out the problem. the damage i was dealing made the enemies hp less then 0 so in the skar dead common event ihad to make the conditional branch 0 or LESS.