In Leo's Tekken Tag Tournament 2 ending, it is revealed that Emma once worked for the Mishima Zaibatsu. In Steve Fox's ending in said game, Emma is revealed to have been a scientist put in charge of observing Steve (or, as the other scientists insisted on calling him, Subject NT01). She was the only one to relate to him as a human boy rather than an experimental subject, but was admonished by her superiors for unprofessional behavior and relocated. Nonetheless, she was still able to help Steve by declaring NT01 dead at age 6 - while in reality, he had been transferred to an orphanage.
In Steve Fox's ending in Tekken 7, Emma was mentioned by Steve as Dr. Kliesen when he finally interrogates his biological mother Nina Williams until she explains to him about how he was created by the Mishima Zaibatsu.