Backstory: Teresa is the older half sister of Jacob Black. Like much of the rest of the shifters she has lived her entire life in La Push. Always trying to look after Jacob her heart broke for him when he ended up leaving La Push after Edward and Bella got together. She had in fact wished to go with him but she ended up staying behind concerned that her presence would only make matters worse. Of course she and Jacob do have a good relationship with one another, but he was a broken wolf, and he needed his space. When Jacob returned and the whispers had begun that he was working with the Cullen family she grew increasingly concerned.
Stepping in, in an attempt to draw him away from the dangerous situation he was managing to get himself into. It was during one of her interventions that she learned that he had in fact imprinted on Renesmee Cullen, which of course put her very much against Jacob's hooking up with Bella, but despite her being overly protective of him, she needed to let him live his own life. His growing up, both mentally and physically had shown even more obvious to Teresa when her brother went against Sam for Alpha.
Facts: Teresa is the first person to tell Jacob when something he's doing is stupid, but she will support him regardless of this.
Personality Traits: Guiding, motherly, and supportive