ANSWER: Rasta (also known as Rastafarian) is a religion created by a Jamaican man named Marcus Garvey. He created it after the crowning of Ras Tafari Makonnen (Haile Selassie I of Ethiopia, also known as Prince Tafari before his coronation) as "King of Kings and Lord of Lords" which took place in Ethiopia in 1930. One of the unique beliefs of Rasta is the use of marijuana (pot) as a "sacrament" and as an aid to meditation. They also command the wearing of dreadlocks as a hairstyle.
Some of the beliefs of Rasta are undoubtedly true, as no religion is entirely a lie. However, the black separatism and the hatred of whites engendered by this movement certainly are antithetical to the teachings of Jesus. Many view the belief in the superiority of the black race, as promoted by Rasta, with skepticism. We are all equal in God's eyes, as Paul wrote that in Christ there is no distinction of race, economic class or even sex. We are all one in Jesus (Galatians 3:28).
You asked if Haile Selassie, the focal point of Rasta, was the highest honored emperor on Earth. Only a few million people, at most, revered Selassie (who died in 1974). This is to be contrasted with other rulers and emperors, throughout history, who have had tens of millions of adherents (China's rulers, etc.) worship them like a god. It is therefore not true that he was the "highest honored emperor" on the planet, even though he was no doubt highly esteemed by those who believed in Rasta.
Marcus Garvey claimed that Ras Tafari Makonnen (Haile Selassie) was essentially God in the flesh, the second coming of Jesus, the Messiah and promoted worshipping him as a god. Furthermore, quoting from a web site related to this group, it is stated "Rasta rejects the Bible used by most Christians, opting instead for a 'black man's Bible' known as the Holy Piby."
The above beliefs are clearly not correct. Scripture is the ONLY valid record of God's dealings with mankind and his communication with us regarding His will, laws, commands and so on that are necessary for salvation (2Timothy 3:15 - 16). Jesus, when he came two thousand years ago, was literally God in the flesh (or God dwelling in flesh) and was the ONLY begotten son of God the Father. Based on many scriptures (John 1:14, 18, 1John 4:9, etc. ) Haile Selassie was not and could not have been "god in the flesh."
Furthermore, when the TRUE second coming of Jesus occurs it will not happen secretly nor take place in a far-flung part of the world unbeknownst to the vast majority of humanity. The whole world will know when Christ is coming back to earth, and that he is doing so with POWER and with the authority to set up the kingdom of God on earth (Revelation 19:11, 13 - 16). Based on the Bible, one must reject Rasta and the overall beliefs of this religious group.