Old completed japanese manga from several years ago (probably ~2010s). It was one of those where two girls got summoned, and they assumed the pretty one was the saintess, but the other girl with a ponytail was actually stronger and only the court mage(?) realized and became her master. but the whole manga, she basically acted behind the scenes and sometimes used her power while hiding to make it seem like the other girl was using it. and then i remember at the end it was hilariously abrupt, and at the end of a battle she suddenly just returned to her world in front of her master's eyes in a very anticlimactic way.
Old completed japanese manga from several years ago (probably ~2010s). It was one of those where two girls got summoned, and they assumed the pretty one was the saintess, but the other girl with a ponytail was actually stronger and only the court mage(?) realized and became her master. but the whole manga, she basically acted behind the scenes and sometimes used her power while hiding to make it seem like the other girl was using it.
and then i remember at the end it was hilariously abrupt, and at the end of a battle she suddenly just returned to her world in front of her master's eyes in a very anticlimactic way.