The opposite of God is Money and Greed....and more people have died for that than in the name of God.
The premise of religion is it's defining variable = God, which is based on a single fundamental function = faith.
Mathematically speaking: Faith = the suspension of logic + critical scientific data processing
Hence, the opposite of God from a mathematical perspective = function of suspending (logic + critical scientific data processing)
Religion at its basis (whether Christianity, Judaism, Hinduism, Buddhism, Islam, etc) is good and sound.
Buddha was born Hindu royalty (Prince Asoka Siddhārtha Gautama), giving up his empire for not comprehending how his religion & God could allow his people to be imporverished, sick & destitute. Buddhism is the only "major" religion to have no God, Buddha is not a God (was neither omniscient or omnipotent), rather the essence of the religion is to achieve the inachievable perfect peace when craving is eliminated known as Nirvana -the abandonment, or extinguishing of all fires that cause suffering namely greed, aversion, and delusion/ignorance.
Ironic isn't it, the only major religion to have no God, is the only one that has never killed or advocated killing - eye for an eye etc..
People are imperfect and distort the education coming from religion.
Some religions groups are better at doing it than others. It used to be Christians for the longest time....
Christians were the first of the major religous based missionaries - Syrian orthodoxy introducing Christianity in India (Kerala) by might & force (4th century), followed by Islam starting some 500 yrs later (first Arab Umayyad caliphate and later Persian Mughal empire).
Data point: only religion without a God never had missionaries, nor did they seek to "expand their empire"....
BTW - I'm not Buddhist & not trying to sell or convert anyone...