Researching photographs of African art for a world history series I kept coming across interesting figure pairs from the Yoruba culture in Nigeria.
It turns out the Yoruba are known for their extraordinarily high rate of multiple births and one of the highest in the world in terms of twin births. At one point in the past twins, known as Ibeji, were thought by the Yoruba to be evil and were quickly killed. However, a cult of twins developed in which the twins were now seen to be minor deities who blessed families with good fortune. The death of either of the twins or both is thought to be calamitous for the family. It must be remedied by appeasing the soul of the deceased child through the carving of a figure put in the care of the mother who will treat the small wooden figure as thought it were the deceased twin and alive. Attention to their ibeji also ensures a peaceful and prosperous existence on earth and prevents the deceased twin from calling their living sibling to the spirit world. Here are a few examples: