Hm the story does match but...
Just for fun I'll sort of create a short battle. For the sake of knowing what happened to what I'll just call them by numbers (In between parenthesis next to when i say a hero did something).
=BATTLE= <==(hope you don't mind i used your title idea x.x)
The last seven heroes (heroes 1, 2, 3, 4, 5, 6, and 7) are at the final battle running and battling through an army of minions on the way to the enemy castle. They all reach the castle, but the mob of minions won't end. Two heroes (heroes 1 and 2) stay and hold back the enemies outside the castle from getting in, the rest go to destroy the warlock. The five remaining heroes (heroes 3, 4, 5, 6, and 7) reach the top of the castle and open the main chamber's doors, almost instantaneously three are zapped by the warlock spell and bound to the ground (Heroes 3,4, and 5). The warlock charges up another blast and tosses it at one of the other heroes. The hero (hero 6) nimbly dodges it but it hits the wall behind her and bounces back, hitting the hero in the back and bringing her down to her knees. The warlock evilly laughs and charges up again setting his eyes on the youngest of the heroes (hero 7). He hurls a ball of fire at the hero, however before it reaches him, one of the heroes (hero 6) counters it with an ice spell and then passes out from exhaustion.
The hero (hero 7) gathers up all of his energy and casts a holy beam at the warlock, holding the warlock in place against the wall and dispelling the warlock's bind on the other three heroes. The three heroes (heroes 3, 4, and 5) then take advantage of this situation and quickly get up and charge the warlock, spearing their swords right through him and killing him.