Why did Ghatotkach have to die in the Mahabharata?

Question

Why did Ghatotkach have to die in the Mahabharata? Was it because his mother was a demon?

Answer 1

The sacrifice made by Ghatotkacha was exactly similar to the sacrifice made by Abhimanyu and his death had nothing to do with his mother being of the Rakshasa race. As sons of Pandavas they were glad to support their fathers in the Great War and of course one who dies a heroic military death is supposed to attain great merit in the afterlife. According to the Mahabharata,

Ghatotkacha the son of Bheema descended upon the Kaurava army like a horror of thousand demons amplified by black magic, becoming unstoppable by night. He threatened to destroy the army and Karna was forced to kill him with the one-time-use divine weapon of Indra which he had been 'saving' for Arjuna. The huge Rakshasa fell crushing thousands of enemy soldiers under his massive bulk. Bheema was disconsolate at the loss of his son but Lord Krishna made them understand that the brave Ghatotkacha had made a great sacrifice for his uncle and opened the way for the Pandavas' eventual victory (paraphrase from the oral tradition which most of us have heard as Indians)

In short nobody survived the Bharata War except the Pandavas, Krishna, Satyaki, Yuyutsu and the "Chiranjeevi Trio." These persons too had to "sacrifice" a great deal by the finish: the Pandavas lost their sons and the Chiranjeevis lost their honor (Kripa, Kritavarma and Ashwatthama, of whom Kritavarma was no chiranjeevi; he was ironically killed by Satyaki at the twilight of the Yadava race, according to Wikipedia); Yuyutsu lost an uncle, 100 brothers and all his illusions of righteous conduct; and for Satyaki and Lord Krishna the ultimate sacrifice was Gandhari's curse that eventually ended the Yadava race. The role of every other soldier including Ghatotkacha was to sacrifice their life for the grand purpose of Dharma and the Divine Plan.

Answer 2

Krishna explains what caused Ghatotkacha's death and how he was happy at his death.

https://www.sacred-texts.com/hin/m07/m07177.htm

"Vasudeva said, Great is the joy I feel. Listen to me, Dhananjaya! This that I will tell thee will immediately dispel thy sorrow and infuse delight into thy heart. O thou of great splendour, know, O Dhananjaya, that Karna, his dart being baffled through Ghatotkacha, is already slain.

He described how powerful Karna is.

The man does not exist in this world that could not stay before Karna armed with that dart and looking like Kartikeya in battle. By good luck, his (natural) armour had been taken away. By good luck, his earrings also had been taken away. By good luck, his infallible dart also is now baffled, through Ghatotkacha. Clad in (natural) coat of mail and decked with his (natural) ear-rings, Karna, who had his senses under control, could singly vanquish the three worlds with the very gods. Neither Vasava, nor Varuna the lord of the waters, nor Yama, could venture to approach him. Indeed, if that bull among men had his armour and ear-rings, neither thyself, bending the Gandiva, nor myself, uplifting my discus, called Sudarsana, could vanquish him in battle.

He also explained how he caused the death of Ghatotkacha through Karna.

Indeed, O Arjuna, for thy good, with the aid of diverse contrivances I have slain, one after another, Jarasandha and the illustrious ruler of the Chedis and the mighty-armed Nishada of the name of Ekalavya. Other great Rakshasas having Hidimva and Kirmira and Vaka for their foremost, as also Alayudha, that grinder of hostile troops, and Ghatotkacha, that crusher of foes and warrior of fierce deeds, have all been slain.'"

https://www.sacred-texts.com/hin/m07/m07178.htm

Hidimva's son also, I have slain by the employment of means, viz., through Karna with his dart.

Krishna also explains how he would slay Ghatotkacha if Karna did not slay him with his dart.

If Karna had not slain him with his dart in great battle, I myself would have had to slay Bhima's son Ghatotkacha. From desire of benefiting you, I did not slay him before. That Rakshasa was inimical to Brahmanas and sacrifices. Because he was a destroyer of sacrifices and of a sinful soul, therefore hath he been thus slain.