Erin Jessica Cahill (born January 4, 1980) is an American actress. She is best known for her roles as Jen Scotts in Power Rangers Time Force (2001), as Ted Mosby's sister, Heather, in How I Met Your Mother (2005), and as Kendra Burke in Saving Grace (2007). She had a recurring role as Felicity in the ABC series Red Widow (2013). She is also noted to be the first lead female character for the Call of Duty franchise, as Chloe "Karma" Lynch in Call of Duty: Black Ops II (2012).Cahill was born in Stafford, Virginia. She began acting in her mother's local high school productions at age four, and started singing and dancing lessons at age eight. She was Miss Pre-Teen Virginia in 1991 and the first runner-up for Miss Junior America. She continued to act into her high school years at Brooke Point High School, where she served as the president of many clubs, including the Honor Thespians group. As a junior, Cahill was the only one of her year to garner perfect scores in all phases of her audition to the Governor's School for the Arts in drama.At age 16, she also won Overall Actor in the Actors, Models, Talent for Christ competition. She was further selected into the Barton and Williams Dance Company, winning both company and individual awards. Following high school graduation in 1998, she attended Marymount Manhattan College in New York on an academic and performing arts scholarship. She left college at age 19 to pursue a full-time acting career in Los Angeles.Cahill was cast as Jen Scotts in Power Rangers Time Force (2001). She began making guest appearances in 2003 in Crossing Jordan: Pathologin mit Profil (2001) and General Hospital (1963). In 2006, she starred in the short-lived Fox series Free Ride (2006). Her first big guest starring role came in 2007 as a 20th-century suffragette in the Cold Case - Kein Opfer ist je vergessen (2003) episode Cold Case - Kein Opfer ist je vergessen: Torn (2007). Since then, she has worked in numerous films and television shows such as Supernatural: Zur Hölle mit dem Bösen (2005), CSI: Miami (2002), The Mentalist (2008), Castle (2009), Ghost Whisperer - Stimmen aus dem Jenseits (2005), Grey's Anatomy: Die jungen Ärzte (2005), and Dr. House (2004).Cahill co-founded Charitable Living, which services the local community throughout the year with various fundraisers and days of volunteering. In May 2015, she joined non-profit group BuildOn and traveled to Malawi to promote education and build schools.