The ajuuraan empire existed from 12-18 and after that there were a civil war between the samaale tribes WHO owned that kingdom.
so now lets go back to 1580. And Remember in this time the portuguese empire were the Worlds superpower + the entire arab World was ruled by the Ottoman for about 300 to 500 years. the only free arab states were Oman & Zanzibar, and they also got invaded by the portuguese empire. so Ajuuraan empire liberated them, and they in return gave tribute to Ajuuraan Empire based in Mogadishu.
Note: the portuguese recaptured the sawahili World, but not Zanzibar or Oman sinces they came under Mogadishu Protection.
Over the next several decades Somali-Portuguese tensions would remain high and the increased contact between Somali sailors and Ottoman corsairs worried the Portuguese who sent a punitive expedition against Mogadishu under João de Sepúlveda, which was unsuccessful.[34] Ottoman-Somali cooperation against the Portuguese in the Indian Ocean reached a high point in the 1580s when Ajuuraan clients of the Somali coastal cities began to sympathize with the Arabs and Swahilis under Portuguese rule and sent an envoy to the Turkish corsair Mir Ali Bey for a joint expedition against the Portuguese. He agreed and was joined by a Somali fleet, which began attacking Portuguese colonies in Southeast Africa.[35]
The Somali-Ottoman offensive managed to drive out the Portuguese from several important cities such as Pate, Mombasa and Kilwa. However, the Portuguese governor sent envoys to Portuguese India requesting a large Portuguese fleet. This request was answered and it reversed the previous offensive of the Muslims into one of defense. The Portuguese armada managed to re-take most of the lost cities and began punishing their leaders, but they refrained from attacking Mogadishu.[36] Throughout the 16th and 17th centuries successive Somali Sultans defied the Portuguese economic monopoly in the Indian Ocean by employing a new coinage which followed the Ottoman pattern, thus proclaiming an attitude of economic independence in regard to the Portuguese.[37]
http://en.wikipedia.org/wiki/Ajuuraan_s ... guese_wars
Now how did those Zanzibaris came to Kismayo?
year--> around 1800 or late 17
After the civil war the empire split into 6 different kingdoms. one in Gedo, one in Hiiraan, one in Ogadenia, one in Barawe and kismayo(Jubboyinka iyo Shabellada hoose) one in bay and finally one in Mogadishu.
Those in jubboyinka were Biyomal&barawense, so they invited Zanzibaris as there Allies to Kismayo. so they can help them fight the others. but few years after that the italians arrived and the Zanzibaris Backstabbed Biyomal and made deal with the italians behind there backs. thats why Biyomal have fought one of the longest war against the italian colony.. Biyomals reputation comes from there war against the italian colony.
after the fall of Ajuuraan bc of the civil war. Oman chose to be still loyal so they gave tribute to one of the 6 Kings.
The Sultanate was governed by the Gobroon Dynasty. It was established by the Geledi soldier Ibrahim Adeer, who had defeated various vassals of the Ajuuraan Empire and founded the House of Gobroon. The dynasty reached its apex under the successive reigns of Sultan Yusuf Mahamud Ibrahim, who successfully consolidated Geledi power during the Bardera wars, and Sultan Ahmed Yusuf, who forced regional powers such as the Omani Empire to submit tribute.
http://en.wikipedia.org/wiki/Geledi_Sultanate
To answer you Question no Arabs on HAGites land sxb.. Biyomal and there new Brothers backstabbed each other. but all in all Biyomal fought a long ass war, i guess the anger of treason gave them extra Motivation to fight.