Here are some synonyms for supplanter:
* Usurper
* Replacements
* Dethroner
* Intruder
* Displacer
* Rival
The word "supplanter" often carries a negative connotation, implying that the person who took the place of another did so unjustly or unfairly.
For example:
* "The ambitious prince was a supplanter, who seized the throne from his rightful heir."
* "The new technology supplanted the older methods, making them obsolete."
* "The company's new CEO is seen as a supplanter, replacing the previous leader who had been beloved by the employees."