Why were Austria-Hungary Ottoman Empire and Bulgaria Germany's allies in World War 1?

Answer 1

Both Austria-Hungary and Germany feared Russia, the Ottoman Empire was also an old enemy of Russia. Also, Germany had been diplomatically isolated pre-WWI by contesting France's takeover of Morroco so that it could demand more colonial territory. Austria-Hungary was one of the few nations it could rely on, and so, although Austria-Hungary was highly aggressive in an unstable area (the Balkans), Germany felt it needed at least this powerful ally. Germany had also been heavily investing in the Ottoman Empire pre-WWI. The Ottoman Empire probably also was angry at Britain for forcing it to make Kuwait autnomous. Bulgaria came into the war after it had started, but it had for a long time desired Macedonia, then a part of Serbia, as part of its country. Bulgaria's royal lineage can also be traced back to the Germany during the time of the war.

Answer 2

It first started off with just Germany and Austria-Hungary, forming the Dual Alliance. When war broke out, Bulgaria and the Ottoman Empire joined the side they thought would win. They did this to gain more land in the Balkans once the war was over. Bulgaria had gone to war with its former Balkan allies over land and lost, and Turkey had practically lost all of the Balkans to the same wars, an area they used to fully control.