usurp

seize and take control without authority and possibly with force; take as one's right or possession

To seize, and hold in possession, by force, or without right; as, to usurp a throne; to usurp the prerogatives of the crown; to usurp power; to usurp the right of a patron is to oust or dispossess him.

Latin 'usurpare' - to occupy illegally

“He was in that yeasty condition of his years when action and reflection alternately usurp the mind; remorse succeeded dissipation, and indulgences offered the soporific to remorse.”

— George Meredith, Complete Project Gutenberg Works of George Meredith

“Upon his death, Nepotian, a family member of undetermined relation, attempted to usurp the crown in place of the future Ramiro I.”