"Good! Russia can support Bulgaria's expansion in the Balkans to the extent that it holds back the other great powers. We will not send troops directly!" Nikolai had calmed down. Despite Ferdinand's tempting promises, the success rate was low, and he did not intend to invest too much.
Despite knowing Nikolai's plans, Ferdinand didn't care. He had already achieved his real goal!
For the sake of secrecy, the secret alliance with Russia must be a secret treaty, and the diplomatic impact will not be too great. Bulgaria can obtain plenty of mining and human resources from Russia and complete industrialization in the short term.
The international situation in the future has changed. Russia lost badly in the Russo-Japanese War and had just restored its strength and caught up with the Great War. Russia had even less chance to fulfill this strategy, and the plan would forever be the plan!
Historically Bulgaria was isolated in the Balkan Wars and will cease to exist. Of course, it is not yet clear, although the pro-Russian faction in Serbia came to power, now they are still the little minions of Austria-Hungary. Russia has no choice of allies at this moment.