The question above is often asked by those who visit Bali for the first time and have heard about Lord Siva, Lord Wisnu, Lord Iswara, etc.
This misunderstanding occurs since Balinese Hinduism mentions the specific lord’s name when they are praying or deliver the offerings.
Even some Balinese declare that they are Shiva or Visnu worshiper. To clarify this misunderstanding many Hindu people from India and Bali as well have provided logical reasons why they have 36.000.004 names of the God.
In short, as other religions, Balinese Hindu community has the only and one God, Ida Sang Hyang Widhi Wasa. However Ida Sang Hyang Widhi which is undefined whether female or male has manifestations based on the function. When Ida Sang Hyang Widhi Wasa creates all creatures in this world, people name it Lord Brahma. In preserving all the creatures God created, Sang Hyang Widhi Wasa has a new name, Lord Visnu. In the manifestation which function is to destroy all creatures and things, Sang Hyang Widhi Wasa is named Lord Shiva.
That God is only one but people name it differently. It is easy to interpret that Hindu people has only one Supreme God with thousand manifestation names. If you are still confused, try to figure this out: many people call Barrack Obama with ‘Mr. President’ because he is the US President. At home when spending time with his family, his daughters call him Father and his wife Barrack. Before assigned as the President, Barrack Obama was a lecturer, so his students will call him ‘Sir’. And his teacher and classmates in Indonesia called him Barry.
In short, all gods and goddesses are a form of the same divine energy. Hindu has only one God but has many names.