Earlier, I wrote a post two weeks ago about the incarnation of the god Vishnu in the form of Rama, the hero of the epic Ramayana. This week, I wanted to say something about Lakshmana, brother to Rama, and considered to be an incarnation of Shesha, the thousand-headed naga or snake-divinity. Shesha is a companion of Vishnu in his incarnations so when Vishnu was incarnated as Rama, Shesha became incarnated as Rama's brother, Lakshmana. Similarly, when Vishnu became incarnated as Krishna, Shesha was incarnated as Krishna's brother, Balarama.
Lakshmana is the constant companion of Rama in his adventures throughout the Ramayana. When the guru Vishvamitra takes the young Rama away to train him, Lakshmana goes along. When Rama is sent into exile, Lakshmana again goes with Rama, together with Rama's wife Sita (previous post about Sita).
A central event in the Ramayana is the kidnapping of Sita by the demon Ravana. Lakshmana's role in this event was critical. In order to get Sita alone, Ravana had to devise a way to get both Rama and Lakshmana away from their encampment in the forest. Ravana therefore compelled the demon Maricha, his uncle, to disguise himself as a beautiful jewel-encrusted deer. The deer then ran by the camp, where Sita could see him. Sita longed to have the deer for her own, and begged Rama to go capture it for her. Lakshmana was suspicious and urged Rama not to go, but at Sita's urging, Rama went to chase after the deer, leaving Sita under Lakshmana's protection.
Rama pursued the deer, and managed to shoot it, but with his dying breath the demon called out, counterfeiting Rama's voice, screaming for help. Sita was terrified at what she heard, and begged Lakshmana to go rescue Rama from danger. Again, Lakshmana was suspicious and did not want to leave Sita alone. Sita, however, absolutely insisted, so Lakshmana drew a circle around their hut, the so-called "Lakshmana Rekha" or "Lakshmana's Limit," that would grant Sita protection. As long as Sita did not cross the line, she would be safe, because no intruder would be able to penetrate the barrier Lakshmana had summoned. Sita, however, voluntarily crossed the line when she went outside to give alms to a poor brahmin - who was none other than Ravana in disguise! So, Ravana thus succeeded in his plan, and was able to kidnap Sita, despite Lakshmana's best efforts to protect her.
The "Lakshmana Rekha" is a phrase still in use in India today, meaning an absolute moral limit that should not be crossed. I even found a reference to a "Lakshmana Rekha" pesticide stick which is for sale - "If a line is drawn with that stick, no ants or insects can cross over" (source). The "Lakshmana Rekha" can also be interpreted negatively, as the limits that men put around women's freedom of movement, as you can read in this article about justice for women in contemporary India. You can find many more instances of modern uses of this term just by Googling "Lakshaman Rekha" and looking at the results you find there.
Many popular depictions of Rama show him together with Lakshmana and Sita, as you can see in this image which depicts them in their forest exile, wearing clothes made of leaves and bark. Rama is shown with blue skin, marking him as a holy incarnation of Vishnu, while you can see Lakshmana in the foreground, skinning an animal in preparation for their evening meal (from a painting done circa 1790):