While most of Africa remained under European control by 1913, Ethiopia remained independent until 1936. What is the reason for this?
You should check out these awesome past answers:
How did Ethiopia successfully avoid colonization? by /u/snackburros and /u/commustar
How did Ethiopia remain independant for so long and then gain support from other colonial powers? by /u/khosikulu
And the discussion in this thread is interesting:
Ethiopia wasn't left alone - it was attacked multiple times by multiple European countries such as Britain and Italy, particularly the latter which was defeated decisively at the Battle of Adwa and successfully allowed for the preservation of Ethiopian independence alongside international recognition. Also, Ethiopia wasn't colonized in 1936 - it was occupied, the Ethiopian Patriots continuing a guerrilla movement that controlled the entire countryside and the Ethiopian Highlands.
Ethiopia managed to survive because it had a strong centralized government, a national identity, access to modern arms and army of hundreds of thousands that was mostly well-equipped in 1895-96.