Today I will start with the Oromo warriors-----the Rayya or Rayyu as Oromo call them. They are part of the larger Barentu branch along with their fellow Wollo native Yejju, Wayyu, Kallu, Kobo, Illu, Humbana, Ittu, the Karayu of Awash basin, the Afran Qallo of Hararghe, Arsi, Qallu of Awash and the Sherifa just to name some.
This particular group is the most Oromo frontier to the north and long assimilated into Abyssinian society. They are long time warriors and almost wiped out the entire Abyssinian elites. They ruled Abyssinia along with their Yejju brothers throughout Ethiopia's long history and also helped Abyssinian Emperors consolidate power including Emperor Menelik II.
Wollo, in northern Ethiopia, is a melting pot of cultures and dozens of ethnics have co-existed since time memorial including the Oromo, Amhara, Tigrais, Agews (Sekota), Afar, Iroba, and the mainly Muslim Argobba people just to name some.
The culture, tradition and music of Wollo is diverse in this sense and has its unique characteristics. The people live in true harmony with one another and even the minority Muslim Argobba exist peacefully in a sea of Tewahedo and Pentay followers. Large population of the Rayyu are Muslim too as are many Tigrais, other Oromo groups, Amhara, etc. In fact, the largest town in Wollo, Dessie, is predominantly Muslim. Ethiopians are mixed people and faiths don't really separate them as one family can have Muslim, Tewahedo (Orthodox) and Pentay (Evangelical) members.
The only downfall for many Muslims was that in the old Ethiopia (Abyssinia), they could not educate their children so they fell behind in literacy and education. Under Abyssinia, the Tewahedo (unity) Church dominated education thus Muslims kept their kids at home. Even with that until the 1974 Derg revolutionary, the Christians did not fair better. 90% of Ethiopians were still illiterate by the time Mengistu Haile Mariam de-crowned Emperor Haile Selassie (Ras Tafari).
The Wollo Oromo especially Yejju and Rayyu always played role in Ethiopia's long history. They rescued Menelik II from prison under Emperor Tewodros II, they started the first rebellion against the royal family (the Raya-Azebo Woyane rebellion hence why present government in Ethiopia is called "Woyane". It was their armies that crashed warlords and feudal leaders as far as Wellega, Illubabor, Benishangul, Gojjam, Hararghe and Tigray. They dominated Mengistu government and they aided the TPLF in its victories against Mengistu. Woyane is like how Landers call Konfuris "Wanlawein". Woyane like Wanlawein was a town in the old Abyssinian administration system.
They maintain sedentary lifestyle built around livestock (there are over 50 million cattle in the Highlands of Ethiopia) and farming; in fact they probably posses the most cattle per capita in the Horn of Africa. They do keep camels too just like the nomadic Somalis and Afar. Like the good old Somalis, they maintain an afro hair which they often style with organic butter just like the Somalis did 80 years ago and the Afar.