Tamsin has grown to be a little bit of a contradiction; First thing, she LOVES people. Loves hanging out with them, being near people, generally talking to people -- Rather, generally talking at all. She's an outgoing soul who doesn't have a mean bone in her body. What she does have is the ability to stick on to any information she has learned of a person. Now, unlike most with this sort of ability, she uses it for good; She's very good at giving gifts, advice, among other things. She doesn't make a spectacle about her remembering the little things, and she doesn't like other people making a big deal about it either. In fact, she doesn't much like anybody making a big deal about her in general. Despite her bubbly personality, she is a sort of secretive person who chooses to let the spotlight go to others - A sense of humility many seem to lack nowadays.
She's also sort of abrasive. While she does not enjoy hurting people, she can sometimes say things that end up hurting another, despite all intentions. She would swear up and down that she did not mean it that way, but an important lesson she has learned over the years, is that she does not get to choose whether she has hurt somebody or not. So, she'll apologise over and over, swearing she'll try to do better. Unfortunately, Tamsin seems to lack a filter most of the time. She is also terrible at keeping secrets. The girl cannot hold on to even the smallest bit of information without letting it slip - Which is not good with the fact that she can sense the future. Fortunately, at the peak of her abilities, she can see visions, but usually the girl will just sense something going on, and not know exactly what it is. To be fair, as a result, it is very hard to surprise her. Though this is a good thing. Tamsin would definitely end up hurting somebody physically, her fight often overriding her flight.
That being said, she's also brave. Very brave. While often she can sense if something is amiss, or wrong, or about to happen, she has learned that often, you cannot change the future, so why attempt to? Sure, the sense may scare her at times, but bravery is not being fearless, it is going forward despite of that fear. She holds on to that like her life depends on it. At times, this can be reckless, but she hasn't gotten any major injuries yet, to be fair.
Family is very important to her. Not only her father, but also, the friends she makes. At some point in her life, she had decided that blood is not the only thing that makes family. A bond can always be broken, of course, but there are certain people besides her dad that she trusts with her entire life. Friends she had made in an early age in school, who would never let her go. Despite her going to a new school, she does keep in contact with these people, not wanting to break her bond with them. Bonds are the most important thing, after all.
Reagan Rory Cassius Trelawney was born a member of the famous Seer Trelawney family and, ironically enough, his father Eldan Trelawney possessed no Seer skill whatsoever. Any and all predictions he made about the future were guesses and, should they come true, were some of the greatest coincidences of all time. Some in the family failed to see what his wife, muggle Jennifer Trenton, saw in him. For all intents and purposes, Jennifer was nothing short of a socially 'perfect' wife. Though a woman who wasn't afraid to stand up for herself, she also was equally as passionate for her family and many members of the Trelawney family thought she'd be a better fit for someone else, not Eldan. Regardless, the marriage was a happy one and fruitful to continue the Trelawney name; Jennifer birthed three healthy sons, each who showed considerable promise in magic from a young age.
Reagan was the middle child, and he showed the most magical prowess, and seer abilities, from a young age. Clearly, he garnered much-expected attention, both in school, and out. Specifically, Tamsin's mother, a Korean woman who lived in England, offered him all the attention in the world. But much to her dismay, he showed no attention towards her. It was an increasing obsession she had with him until one day, she took him out for a drink, and drugged him... And the night went on. The next month, she revealed a pregnancy - With Reagan's child.
Reagan knew about Tamsin from the beginning, sure, but he wanted absolutely nothing to do with the woman who gave birth to her. As a response, and thanks to Reagan's love of children, he made a deal with her. A co-parenting situation. Her mother had her one month, and Reagan the next. But really, Tamsin preferred Reagan over her mother. Especially because he seemed to understand her better.
He didn't freak out when, at seven years old, she exploded her pillow in a fit of rage. He didn't freak out when she showed the same signs he did as a child, blurting out things to come in her everyday life, though nothing as big as a death (At least, not a human's. She did predict the death of her pet bunny. But she wasn't too shaken up about it.) But, signs of seership nonetheless. Later the same year as her sign of magic, Tamsin's mother decided to give Reagan full custody, and went her own way.
For the first decade of her life, the deal wit her parents went off without a hitch. Tamsin, as a result, is a truly cultured girl. When she had shown signs of magic, both Reagan and her mother were excited. Tamsin, over the years, had nothing less than a fairytale relationship with both of her parents. So, when she had gotten a letter to both Hogwarts and Mahoutokoro, they let her decide where to go; Without hesitation, she chose Hogwarts.