Mahaparsva, on getting the info about the killing of his pal Mahodara by Sugreeva, was totally stunned. Then he decided to avenge his killing by liquidating Angada and his army who were in his close proximity. He then exerted his full prowess on the army of Angada with his men and arrows. Very many vanaras including the chiefs under that army of Angada were tormented and the heads of many of them were swept down just like an hurricane would throw down fruits from their stalk.
That rakshash Mahaparsva started hurling innumerable arrows towards the vanaras. Those arrows chopped off the arms of some vanaras and struck down the region of the ribs of some others. All the guys in his army followed suit. As the hurling of the arrows by Mahaparsva and his army was so sudden and so multitudinous, the hapless vanaras were totally at a loss as to how to defend themselves. Tormented by the flight of abundant and copious arrows of Mahaparsva and his chaps, all those vanaras were downcast with despair and lost heart.
Seeing his army depressed by the torments of the rakshashas, Angada, who was endowed with a great impetuosity, acted like lightning. Taking hold of a steel rod, which was quite strong and sturdy, hurled it on Mahaparsva with all the force he could muster. It found its target. The sudden hit like a bolt from the blue made Mahaparsva senseless and fall on the ground from his chariot. Seeing that, Jambavan killed the charioteer and horses. Not satisfied with that he he broke the chariot to pieces.
The very strong and sturdy Mahaparsva regained his conscience very quickly and resumed his strikes with his arrows on Angada. He struck Jambavan, too with three arrows in his chest and struck Gavaksha, too. Ignoring the pain caused by the arrows of Mahaparsva, Angada seized hold of a terrific iron rod. (Do not ask me 'How such and many iron rods were found in the battle field ? I intent asking Maharishi Valmiki if and when I meet him). Firmly holding that iron rod, Angada hurled it on Mahaparsva. This time that iron rod knocked the bow with the arrow fitted to it, from the hand of that rakshash and also his helmet.
Seeing that rakshash was not dying Angada jumping like a monkey, as he was, over to him, slapped him on his temple. Unfortunately the slap was not forceful enough to kill that rakshash. Mahaparsva took a huge axe in his hand and hit it on Angada. Angada evaded that axe with alacrity.
Angada determined to kill that rakshash in his next move. Tightened his fist, Angada punched that rakshsh on his chest with all the force he derived from his illustrious dad Vali. With the blow of that fist in that great combat, the fleshy part of his heart was blasted and he fell down dead on the ground. When Mahaparsva fell dead on the ground, his army got confused. Ravana went almost mad with desperation.
Seeing the killing of Mahaparsva all the vanaras started roaring like a lion and dancing happily. Hearing and seeing that rejoicement, Ravana decided to do the fighting himself.