Hai-yu Island is a location in Sonic the Hedgehog: Crystals of Soleanna. It is an ancient, peaceful and mysterious island located from far away from Mobius. It is also the place were Inferno the Cat was born and raised on.  


The life in the Hai-yu Island is not perfectly known yet, and scientists have tried to find how the inhabitants/residents live there; which is still unexplained today. However, Inferno knows about it; but whenever somebody asks her a question about the ecology, she will respond "'s up to you do decide!".


The climate in this location is spring-like. It never snows, rains, nor even winds blowing.


For nearly 100,000 years ago, there was an outbreaking war agains these from Mobius and these from Bygone Island. When a veteran and traveller named Sun-yang Gong was getting sick while riding a large ship, he suddenly landed into the island and thought that it was Green Hill Zone , and it became a French colony. The former Hai-yuans got eradicated by getting taken and used as slaves due to their "annoying culture" and "ugly traditions". The now-modern Hai-yuans were taken to the island as a punishment for bad crimes.


The Hai-yuans' religion is mainly Awanism, where the awanists believe that whenever you dream, you get taken higher up in the sky and gets encountered by friendly gods, goddesses and deities.

Significant Populations

The island is now populated by modern Hai-yu Islanders and pretty strange but powerful spirits called the "Xiao-lans". 

Notable Areas

  • Jun-woo
  • Kiriri
  • Shun-chan Sue


None of them.

Known Hai-yu Islanders (Hai-yuans)


  • The island's history is alot similar to when Christopher Colombus discovered America and thought at he was in India, and when the Australian tribe called Aboriginals got taken as slaves and James Cook claimed it to be a British colony along with English men being sent to the country as a punishment for bad crimes, such as stealing for example.
  • The name Hai-yu, translates to "Also - and" in Chinese. 
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