The antonyms for "kept in existence" are numerous and can be expressed in various ways. Firstly, a common antonym is "cease to exist," which implies that the thing or entity is no longer present or operational. Other antonyms can include "extinguished," "annihilated," or "obliterated," which all suggest a complete end to the existence of the entity in question. Alternatively, one can use phrases such as "let go," "abandoned," or "discontinued," which imply a deliberate decision to end the existence of an entity. Overall, the antonyms for "kept in existence" represent a variety of ways in which something can come to an end, whether voluntarily or involuntarily.