I do not think there were any subjects on the relations between Russia and Ethiopia at the time of Nicholas II.
I have been studying this question for some time, especially through the books of Alexander Boulatovich, Piotr Krasnov and Nicolas Leontiev. There are even Nicholas II mountains in Abyssinia (a chain of volcanoes).
In Krasnov's book, there is a funny anecdote. The Russian lieutenant offers a watch to an Ethiopian village chief. On the watch is an engraved portrait of Nicholas II. Krasnov explains to the village chief who he is, and the village chief replies: "We have heard a lot about the great ruler of Moscow, and during the war with the Italians no one came to take care of the Abyssinian wounded. but the Tsar of Moscow sent his doctors. "
Very interesting books on the report of the Russians to Africa, to the colonization, to the other colonial powers, and to the look on the African customs and tradition.
I will try to put links to these books not always easy to find.