Around the time the comic San Salvador's Story took place, Mark's step father's family came to Green Bay, Wisconsin from Arizona. According to Mark, he decided to be a "good cousin" to Daniella, so he showed her around town. When "San" Salvador Martinez had one of his awesome parties, Mark decided to take Daniella with him there. However, Mark had already agreed to go to Kate. Although it was never seen in the series, Kate had seen Mark hanging out with Daniella at the party, and she got suspicious. Thinking that Mark had cheated on her, she then breaks up with him.
At Packie and Francis McReary's New Year's party, Kate is still upset about Mark after they had broken up two months ago. Salvador Real Arrayga, a friend of Packie's, comforted Kate at the party, and Kate fell in love with Salvador. However, Salvador wasn't very excited about the idea of dating someone seven years younger than him.
Kate and Salvador continued to date throughout 2014, until July 2015, when they hang out at the town's local pool. Mark, who sees the two together, becomes upset and tells Tony Gonzales (who remembers him from San Salvador's party) that it was all a big misunderstanding, and Daniella is his relative, not his new girlfriend. Tony encourages Mark to try to tell the truth to Kate. Mark thanks him, and walks up to Kate. She isn't happy to see her ex-boyfriend, and tells him to go away, because she is hanging out with her new boyfriend, Salvador.
Mark then explains to Kate about everything with Daniella. However, Kate still refuses to believe him. Mark then holds her hand and asks her if he would ever lie to her. Surprised to see her hand being held by Mark, Kate then looks at Mark, who begins to cry. She glances to Salvador, who is watching everything a few feet away. Looking back at Mark, she replies to his question with "No Mark. No, you would never."
Kate hugs Mark and tells him that she missed him, and Mark said he missed her too. Confused, Salvador asks Kate "What about us?", to which Kate apologizes to him and tells him that they are through. She says Mark is a much better boyfriend than Salvador, which hurts his feelings. Salvador walks away by himself as Kate and Mark walk into the sunset holding hands.
It is unknown what happened to Daniella, although it is likely that she returned back home to Arizona with her family.
- Although being a mere coincidence, her name sounds similar to Danielle Spencer, a character in the old Nickelodeon sketch comedy show The Amanda Show, specifically in the skit "The Girls' Room".
- There is also an actor named Danielle Spencer in real life.
- She is one of two characters in the series to never appear in person, only being mentioned by other characters, the other being Giovanni Ancelotti.
- Sibling Rivalries
- Happy New Year! (mentioned only)