There is another view about the birth of Ravana and his brothers. This is mentioned in Mahabharata – Vana Parva – Ramaupakhan parva (रामोपाख्यान पर्व) – chapter 275
पुलस्त्यस्य तु यः क्रोधादर्धदेहोऽभवन्मुनिः।
विश्रवा नाम सक्रोध: स वैश्रवणमैक्षत | 1
Due to the anger by Rishi Pulastaya (पुलस्त्य), Vishrava (विश्रवा) was born from other half of his body and soon after his birth Vishrava looked at Lord Kubera (वैश्रवण) with anger.
बुबुधे तं तु सक्रोधं पितरं राक्षसेश्वरः।
कुबेरस्तत्प्रसादार्थं यतते स्म सदा नृप । 2
When Lord Kubera came to know that his father is not happy with him, so he tried to do actions for his happiness
स राजराजो लङ्कायां न्यवसन्नरवाहनः।
राक्षसीः प्रददौ तिस्रः पितुर्वै परिचारिकाः 3
Lord Kubera was use to live in Lanka, and he use to travel in a cart carried by humans. He appointed three girls for the service of his father Vishrava to make him happy.
पुष्पोत्कटा च राका च मालिनी च विशांपते।
अन्योन्यस्पर्धयाराजञ्श्रेयस्कामाः सुमध्यमाः 5
The names of those three girls were Pusphutkata, Raka and Malini. they use to compete each other in serving the Vishrava.
पुष्पोत्कटायां जज्ञाते द्वौ पुत्रौ राक्षसेश्वरौ।
कुम्भकर्णदशग्रीवौ बलेनाप्रतिमौ भुवि ।। 7
Two sons were born from Pusphutkata – Ravana (दशग्रीव) and Kumbkaran (कुम्भकर्ण). They both were the leaders of Asuras. There were no one as strong as them on this earth.
मालिन जनयामास पुत्रमेकं विभीषणम्।
राकार्या मिथुनं जज्ञे खरः शूर्पणखा तथा ।। 8
Malini gave birth to Vibhishan (विभीषण) and Raka gave birth to a son and a daughter. there names were Khara (खरः) and Supranakha (शूर्पणखा)