Who is Elder Rama or Indrajit

Why was Laxman injured by Indrajit's Shakti weapon?

First, Indrajit never tried to use a Brahmastra, Narayanastra, or Pashupatastra during war (although he did use a Brahmastra against Hanuman during Hanuman's visit to Lanka, as I discuss in this answer). But he once used another weapon used by Shiva, the Raudrastra, although, as I will discuss below, this was only used to ward off one of Lakshmana's weapons. Second, the TV series brings together a number of different incidents:

  1. There is one occasion when Indrajit mortally wounded Lakshmana, but this is one occasion when he mortally wounded both Rama and Lakshmana. As described in this chapter and in this chapter of the Yuddha Kanda of Ramayana, Sugriva's nephew Angada defeated Indrajit in battle at the beginning of the war so that Indrajit became invisible and then fired numerous Nagastras (snake weapons) at Rama and Lakshmana in a state very close at death. But then Vishnu's Mount Garuda came into play, ate all the snakes and healed the wounds of Rama and Lakshmana. (Rama asked him who he was and why he was helping them, but Garuda refused to answer because Rama was not supposed to know that he was an incarnation of Vishnu.)

  2. The only direct confrontation between Lakshmana and Indrajit occurred later in the war, and its conclusion is described in this chapter of Yuddha Kanda. Indrajit fired a yamastra (weapon of the god of death Yama), but Lakshmana destroyed it with a kuberastra (weapon of the god of wealth Kubera). Then Lakshmana launched a Varunastra (weapon of Varuna, the ocean god), but Indrajit destroyed it with a Raudrastra (weapon of Shiva). Then Indrajit fired an Agneyastra (weapon of Agni, the fire god), but Lakshmana destroyed it with a Saurenastra (weapon of Surya, the sun god). Then Indrajit launched an Asurastra (weapon of the demons), but Lakshmana destroyed it with a Maheshwarastra (another weapon of Shiva). Finally, Lakshmana hit Indrajit with an Indrastra (weapon of the Indra king of the gods) and killed him. After Laskhmana killed Indrajit, he had several wounds, but those wounds were very easily healed by Sugriva's father-in-law Sushena.

  3. The incident you mentioned, in which Hanuman carried a mountain, occurred later in the war and had nothing to do with Indrajit. As described in this chapter of Yuddha Kanda, Ravana's brother Vibhishana killed Ravana's horses during the battle between Rama and Ravana. Ravana got off his chariot and threw a mighty spear at Vibhishana, but Lakshmana shot the spear with three arrows. Annoyed by this, Ravana threw Lakshmana an even larger spear and mortally wounded him. As described in the next chapter, Sugriva's father-in-law sent Sushena Hanuman to fetch the herbs Vishalya Karani, Savarni Karani, Sanjiva Karani, and Sandhana Karani from the top of Mount Oushadi. Hanuman couldn't identify the herbs on this mountain, so he brought the mountain top to Lanka himself, and then Sushena used the herbs to heal Lakshmana.

So it is not even a question of whether Lakshmana is susceptible to some Astras (magical weapons) and not others, for there is never an occasion when he shows invincibility against Astras.

Amrit Dhara