Malevolence appears as a purple, bubble-like substance that infiltrates a being such as a human, a seraph, or an animal, and, in great enough quantities, transforms the carrier into a "hellion" in Zestiria or a "daemon" in Berseria. The level of malevolence corrupting a person or vessel's body determines what type and strength the being will become and receive once transformed into a hellion. Malevolence is impurities born from the negative emotions of humanity, ultimately threatening the existence of humans and seraphim. In some locales, it is visible as a purple particle moving horizontally. Only a Shepherd and those working in concert with them, through the power of the Prime Lord seraph, have the power to purify malevolence. However, there have been cases where certain people can control malevolence at will without being transformed by it, such as when Melchior Mayvin uses a sphere of malevolence to turn three malakhim into wyverns and Innominat turns Silva into a Hellkite and attempts to turn Laphicet into a dragon only for Laphicet's silver flame to disperse it.
All animals infected with malevolence can transform into a mythical being from inspired legends and mythology, or a more powerful and elder form. Examples include a bird transforming into a harpy or a dog into a werewolf. Important factors such as environment, lifestyle, relationship, temperature, feelings, and emotions determine the appearance of a human or seraph, unlike an animal, which will simply further evolve or mutate. There are also fixed-gender hellions. Some examples include Medusa, Echidna, and Succubus hellions, all of which can only be derived from a female being.
In Tales of Berseria, it is revealed that malevolence comes into eight different types depending on the emotion enticing it: lust, greed, selfishness, obsession, cowardice, conceit, hatred, and despair.
Malevolence in this regard is the result of a curse. When seraphim descended from the heavenly realm, wishing to live in harmony with humans, those seraphim who did not seek co-existence with humans and remained in the heavenly realm cast this curse upon the world. While humankind had always generated malevolence, it would now cause the horrible transformations described above. With lack of proper term during this era, the masses refer to it as daemonblight.