Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 10: Ṛśyaśṛṅga Comes to Romapada’s kingdom
Text 1.10.12

कस्त्वं किं वर्तसे ब्रह्मञ्ज्ञातुमिच्छामहे वयम्।
एकस्त्वं विजने घोरे वने चरसि शंस नः॥

kas tvaṁ kiṁ vartase brahmañ jñātum icchāmahe vayam
ekas tvaṁ vijane ghore vane carasi śaṁsa naḥ

kaḥ = who; tvam = are you; kim = why; vartase = are; brahman = O brāhmaṇa; jñātum = to know; icchāmahe = desire; vayam = we; ekaḥ tvam = alone; vijane = in this unpopulated; ghore = terrible; vane = forest; carasi = you here, wandering; śaṁsa = please tell; naḥ = us.

O brāhmaṇa, we desire to know, who are you? Why are you here wandering alone in this unpopulated terrible forest? Please tell us.

“Who are you?” [in this context] means “Whose son are you?”