‘-1,391!’
Every single attack of the monsters inflicted Zhang Yang with approximately 1,400 points of damage value. Zhang Yang did not dare kite both the monsters by himself, so he only kited one of the monsters and allowed [Mythical Turtle] to block the other monster.
When his health points were beginning to run low, Zhang Yang would take a bottle of grade-5 transmuted [Troll Recovery Potion], or a [Fountain of Life], or activate {Berserker’s Heal}, depending on the situation.
While waiting for those activated skills to cool down, Zhang Yang did not forget to throw his [Spear of Obliteration] onto the boss. Even if he could just reduce a 1 second period of time required for Kent to slay the boss, it would definitely reduce the pressure on him in blocking the monsters by the stairs as well.
1. Trying to put out a burning cartload with just a cup of water -- an utterly inadequate measure.