Timur was a (partial) Mongolian from Iran, one of the four major divisions of the Mongolian Empire. (The other three were Russia, Kazakhstan, and Mongolia-China. As such, he was "more royalist than the king," regarding the Mongol empire.
His first step was to unite the former Mongolian Iranian territory under his rule during the 1390s (although he also advanced further into India than Genghis Khan). Then he conquered much of "Mongolian" central Asia (Kazakhstan, etc.) Finally, he planned to make war on the Eastern Mongolian empire (Ming China and the Mongolian homeland), but died in 1405 before he could do so.