The legends say that his mother Emese seen a divine dream of a Turul bird which flied over her and got her with a child; she seen it as her womb was the origin of many sources of great kings, but they will multiply on foreign lands. (That's why Álmos is called such, as the name means: The Bedreamed One). Although this seems weird compared to the christian mythology it justified the divine origins of the Hungarian leaders.
He strengthened the alliance between the tribal leaders, and he probably led the movement to secede from the Kazar imperium. He successfully kept his son Árpád in power on the contrary of the tribal practices. The raids were widespread, and the tribes sucessfully settled in Etelköz, where they were able to fight back the Besenyő attacks and getting stronger by them.
His death, according to the legends, which said "he is going to found a great line of emperors but he must not enter the land of Pannonia", was probably caused by either assassination or human sacrifice, but we do not have informations on the beliefs of the tribal world.
It is to note, that the two legends concerning Álmos's conceivement and death are reported to us by 13th century (already christian) scholars in medieval codices, who have lived 400 years after the actual life of Álmos, and that the two legends show very strong parallels to christian mythology. It is possible, that the author has borrowed elements from Maria's coceivement by the Holy Spirit for his birth, and Moses not being allowed to enter Kanaan after leading the Jews to the Holy Lands for his death.