(The map below shows Romania during World War I, with Transylvania being part of Austria-Hungary during the war and incorporated into Romania afterward. The region is mostly inhabited by Romanians but was under Austria-Hungary's rule. This conflict was the main reason for Romania joining the Allies in the war against the Central Powers.)
"Oil, General." Shire analyzed: "Oil is the lifeblood of the Germans. Once Romania announces its joining of the Allies, the Germans will undoubtedly launch an attack against it and strive to defeat it in the shortest possible time."
Gallieni was taken aback and nodded slightly.
Prior to this, everyone, including Gallieni himself, thought it was good for Romania, the oil-rich nation, to join the Allies.
But as Shire mentioned, once Romania announced joining, the Germans would capture Romania and control the oil.
Shire continued analyzing as he faced the map:
