I bring war but i also bring love,
people belive in me altough they cannot see me.
i create but i destroy.
what am i.

Spirits or gods is the answer.

Explanation:

answer: cannibalism, the capac raymi, capacocha, the eight day feast, the combing of the hair

explanation:

the incas have many rituals, cannibalism was always a very ritual thing, which was normally tied to sacrifices, warfare, death, and regeneration.

  the capac raymi was one of the most important ceremonies. it occurred around the summer solstice and was when they worshiped their sun god, also known as inti.

  the capacocho was another one of their most important ceremonies. it was when many children where selected to start their training, and these children where destined to become sacrificial blessings to their sun god, inti. being chosen for this ritual was a blessing.

  the eight day feast was a feast that lasted 8 days and, each day, the day began with a chanting at dawn. a follow up song at noon. which ended with complete silence at the end of the day. on this day, inca royalty was always dressed in silver and gold laced clothing.

  the combing of the hair was the most important ritual to young girls. this ritual was known as the coming of age ceremony, but only the most beautiful girls where chosen. in this ceremony, the girls chose their new name and where chosen as either brides, or princesses of rulers.