Number 1 is Brahma - the creator. In statues you recognize him by the four faces looking to the north, east, south and west and his four hands. He rides a swan or sits on a lotusflower. His wife, Saraswati, is the goddess of education, music and arts.
Number 2 is Vishnu - the preserver. He is the protector of the universe. On paintings and statues he sits on an eagle or sleeps on a giant snake. Lord Vishnu is married to Laksmi, the goddess of prosperity, purity and generosity. Vishnu can manifest himself in at least ten different appearances. The most famous of those are Rama and Krishna, the main characters of the Ramayana story.
Number 3 is Shiva - the destructor. He destroys the evil in the universe and he is believed to create new lives when he dances. He possesses a third eye in the middle of his forehead. His symbol is the trident. In the majestic groupsstatues he is the one riding a bull. His wife is Parvati, the goddess of love and devotion. She is the mother of the gods Ganesha, with the elephant face, and Skanda, the god of war.
Beside these three gods there is a large amount of other appearances or incarnations of gods, all derived from that same supreme spirit Sanghyang Widhi Wasa. Important and usually invisible presences are also the spirits of the ancestors, who are believed to have a crucial influence in the lives of their families. During the 10 days of the Galungan - Kuningan celebrations they all descend to the earth (Bali) and are welcomed with penyors (beautifully decorated bamboo poles) and many special offers. On the last day, Kuningan, they return to their heavenly homes.
Of course where there is good, there is evil, also amongst the higher spirits. It is comparable to the dark sides in our own characters. Evil can materialize in demons, monsters or spirits. But also in practitioners of black magic, who put a harmful spell on you.
According to the Balinese Hinduism not only everyone, but also everything has a soul: animals, trees, keris (traditonal daggers) books, houses, stones, rocks, rivers, even mountains. All can be inhabited by good sprits or demons and other bad spirits.