Legends around the world portray tigers in a multi-faceted fashion, as both heroes and villains. In Asia, being compared to a tiger is the highest honor bestowed upon admired and feared historical figures. There are three prime examples of this, each belonging to China, Korea and Japan.
The earliest example, Sun Jian, was never an Emperor in his lifetime. He was a feudal lord who earned his reputation by fighting pirates and bandits. He became an Emperor posthumously when his son, Sun Quan (AD 182-252) established Wu and proclaimed himself an Emperor
King Kyeonhweon was not called a tiger, but a Korean legend tells that a female tiger came to breastfeed him under a tree while his parents were busy working their land. The story foreshadows his prowess as a warrior king.
Takeda Shingen ruled Kai province of Japan and was one of the best military commanders of his time. He remained a regional lord until his death. The clan was absorbed by other factions. Nevertheless, Shingen has been one of the most popular historical figures in Japan for centuries.
These men earned the nickname of a tiger or were compared to one, because they were powerful military commanders as well as charismatic leaders, but their stories also have dark sides.
King Kyeonhweon was eventually overthrown and exiled by his eldest legitimate son when he tried to name one of his younger sons, possibly illegitimate, as an heir.
Takeda rebelled against and exiled his own father to become the head of his family.
Sun Jian didn’t experience any familial conflict, but his premature death left his sons with a heavy task of re-establishing the family and they failed to unify China.
The Portraits of Sun Jian and Takeda Shigen are in public domain, but the portrait of Kyeonhweon is not. I have shared the link to a Korean article that features a portrait of the king. It is drawn by a Korean artist and based on the historical description.