It means that even if someone looks weak, you should not mess with them because you never know who is behind them.
It comes from how threatening or attacking Lemun will cause the symbiotic giant animal Lerun to attack in a rage.
The phrase “don’t kick Lemun” is a common phrase used in movies and novels when people warn someone, like, “Hey, don’t mess with them (because there are bad guys at the back).”
In areas where Lemuns dwell or are raised (for fur), phrases based on the symbiotic relationship between Lemuns and Leruns is almost always used.
Example of phrases based on the symbiotic relationship between Lemun and Lerun
・Lerun’s anger
・Kick Lerun but never Lemun
・Lure Lerun with Lemun
Translation note
Lemun: An animal with a position comparable to a dog or cat on Earth. It is extremely friendly and intelligent, and therefore many people tend to live with it as a family. It is well known for its exceptionally close symbiotic relationship with Leruns, the largest herbivore on land. The Lemun takes care of Lerun juveniles, and in return, the Lerun becomes violent and fights with all its might when a Lemun is attacked by predators.
Lerun: The largest herbivore on land. They have been raised since ancient times because of the high-quality fur they produce. Leruns and Lemuns are well known for their extremely close symbiotic relationship. In return for a Lemun taking care of Lerun juveniles, Leruns fight with all their might for them when a Lemun is attacked by predators such as Valood. There are many myths, folklore, and proverbs related to this relationship. Leruns are also called “guardians” since they can protect humans just like how they protect Lemuns if a trusting relationship is established.
Reference
“Dictionary of Proverbs by Biological Species ‘Lerun’” (Direlle Aarti)
“Dictionary of Proverbs by Biological Species ‘Lemun’” (Direlle Aarti)