She settled on the outskirts of a village. She was doing some investigative work for a local farmer when she fell though a sort of dimension door to Sigil. She found the Sensates' grounding in the tangible familiar and comforting, so she joined them, but she's not a zealot.

Marissa has experinced much in her young life, collecting many memories, many lasting impressions. But a handful are lodged deepest within her. The smell of her mother's scent as she hugged her farewell for the last time. The taste of flesh the first time she kissed another. The feel of the pounding of her heart in her chest the first time she engaged in combat. The fading sound of her hedgehog companion's frantic squeaking as she tumbled throught the dimensional portal. The wondrous sight that greeted her eyes as she arrived in Sigil.