Sherry appears in Academy City with the intention of attacking a person of importance to either Academy City or Necessarius in order to cause a conflict and eventually, war between the two factions. During her assault, she reveals to Tōma that she seeks to keep science and magic divided as revenge for her late friend Ellis, an esper from Academy City. Ellis was involved in a secret experiment 20 years ago between Academy City and a faction of Necessarius in an attempt to create the first magician-esper hybrid. But it failed as not only did the espers participants suffered major injuries from magic but were killed by the Knights of England as the experiment was illegal under the truce between Science and Magic. Blaming both sides for letting Ellis suffer and be killed, Sherry swore revenge against them by making them suffered like she did.