6. Ravan was well-aware of his impending doom.
Most powerful Asuras (demons) knew that they were sent to earth to perform a particular role. Ravan knew that it was his fate to die by the hands of an avatar of Vishnu, something that would help him attain moksha and give up his demon form.
7. Ever wondered why Ravan had 10 heads?
Some versions of the Ramayan say that Ravan did not in fact have ten heads, but it appeared so because his mother gave him a necklace of nine pearls that caused an optical illusion for any observer. In another version, it is said that to please Shiva, Ravan hacked his own head into pieces, but his devotion made each piece spawn into another head.
8. He got the name Ravan later in life, and that too from Shiva.
Ravan wanted Shiva to relocate from Kailash to Lanka, and to make this possible, he tried to lift the mountrain. But Shiva, being who he is, put down his foot onto the mountain, thus crushing Ravan's finger with his one toe. Ravan let out a huge roar of pain, but at the same time, he was so enamored by Shiva's power, he performed the Shiva tandav stotram. It is believed that Ravan plucked out nerves from his own hand to provide accompanying music. Shiva, thus impressed, named him Ravan (the one who roars loud).
9. Ravan was shamed by his own wife, which eventually led to his downfall.
When Ram's army was slowly defeating Ravan's, and he was the only one left alive, Ravan decided to perform a powerful yagya to turn the tide. But it required him to stay put and not leave his spot. Seeing this, Ram sent Angad, Bali's son and his vaanar sena to disrupt the yagya. After they failed to do so, Angad dragged Ravan's wife Mandodari. Ravan still didn't move. Then she screamed at him and shamed him by telling how Ram was fighting a war to get his wife back while Ravan wasn't moving from his spot to save his wife. Ravan finally moved, leaving his yagya incomplete.
10. Ravan and his brother Kumbhkaran were actually avatars of Vishnu's gatekeepers.
Ravan and his brother Kumbhkaran were actually Jaya and Vijaya, the gatekeepers of Vishnu, which made them a little arrogant. So much so that once when the four Kumaras, mind-born sons of Brahma showed up at the gates of Vaikunth (Vishnu's abode), Jaya-Vijaya mistook them for naked children (a result of their tapasya). This enraged the sages so much, they cursed Jaya-Vijaya saying that they would be parted from their lord. When they asked for forgiveness, the sages said that they could either spent seven lifetimes on earth as Vishnu's avatars' allies or three lifetimes as their enemies. They naturally chose the latter. In one of those three lifetimes, Jaya-Vijaya were born as Ravan and Kumbhkaran.
The essence of Indian mythology is obviously beyond the simple good vs evil trope. If you care to dig deep, there's an interesting story at every step.
Ravan played his role as a villain, but it was that of a much-needed villain, that brought balance to the equation. No wonder there are many people in the world, who still worship him.