Had they seen black people before? Where they sympathic towards them? Did they care at all?
Where are you talking about? The US? The Caribbean? Central America? South America?
You might check out the answers to these questions:
During the period when Africans were enslaved in America, what was the social status like for Native Americans?
What did the Native Americans think of African slaves?
What were the Native Americans' attitude towards African slaves like?
Were any Native Americans enslaved?
In colonial America, what was the extent of interaction like between Native Americans and African slaves?
Did Native Americans help runaway slaves? Were slaves ever integrated into Native American tribes?
How did the Cherokee and Creek nations acquire African American slaves? Would African Americans generally be better off under a Native American owner or a poorer white owner?