Kevin explains that some humans that look normal may be part alien. According to Kevin, people with alien ancestry are actually pretty common on Earth. They are especially common among the offspring of Plumbers.
Humans are one of the few known species that can perform magic and manipulate mana, however only certain individuals have the talent.
As the attributes of humans are well-balanced mentally and physically, they are able to survive in almost every kind of environment. This also negates the weaknesses of alien hybrids, who are half human. For example,Ester, who is half Kraaho and half human, describes Earth's surface temperature as "nippy", whereas a pure Kraaho would be at great discomfort on the surface.
As seen throughout the series, humans are excellent climbers, shown to be able to climb almost anything.
Humans are very adaptable both mentally and physically, been able to adapt to environment changes quickly and figure out how to deal with unexpected and stressful situations better than most species.
Humans are the best long distance runners on Earth, one hunting tactic employed by ancient humans was to chase their prey until it became too exhausted to continue fleeing.
Compared to many alien species, humans are about average or below average in almost every mental and physical aspect, making them easy to beat.
Humans are vulnerable to DNA-targeting weaponry such as a Tachyon Cannon, due to the fact that their DNA only varies by less than 1% from person to person.
Any strength humans have usually comes from their numbers, making them highly vulnerable when alone.