Since it is accepted and clear that Kara Thrace was a Seraph, did this Seraph have those weird visions/etc that lead her on to the suicide mission in the viper?
What exactly pushed her to kill herself? Why did this Seraph want to kill herself?
Since it is accepted and clear that Kara Thrace was a Seraph, did this Seraph have those weird visions/etc that lead her on to the suicide mission in the viper?
What exactly pushed her to kill herself? Why did this Seraph want to kill herself?
First of all, I would be hesistant to call anything about the Battlestar Galactica finale accepted, and definately not clear. Large portions of it were left ambiguous on purpose, and I'm pretty sure Starbuck's nature/role was one of those things.
However, you are correct that the most popular and best-known fan theory is that she was some sort of angel. This theory generally accepts that Kara was human up until the point that her Viper appeared to explode, though it instead jumped to old-Earth with her inside, dead.
From that point on, the theory goes, she is resurrected as an angel, though unaware of her own nature (or else a really good in-universe actress). Every action she takes from that point onward is geared towards leading the humans to Earth.
As far as why the human Kara was willing to fly into the star and explode, keep in mind that she had just finished having a vision of a head-Leoben (an avatar like the head-Six and head-Baltar) who told her to stop fearing death and follow her destiny. Also, she did not actually explode, but was somehow transported away to old-Earth. She seems to have sensed that something deeper was happening to her at the time. Therefore, she must have decided that flying into the solar storm was part of her destiny, even if it meant potentially dying.
She said she wasn't afraid anymore to Lee right before her plane exploded. All she could think about was either death, (due to her childhood upbringing and the sheer fact that fighter pilots have to be a little friendly with the concept of death,) or her part in finding earth. The idea, the pull of her "destiny" and that it was already written for her, it wasnt suicide, it was trusting and accepting the voice that told her she would find earth, and that there was nothing to fear.
As for when she comes back, I believe that she is an Angel. Her fate and Anders had to be intertwined as love is such a strong theme in the show. Everything they ever did was for each other. In life or in death, it was her destiny to find earth, and once they finally found it, as Anders put it when she said her goodbye "Ill see you on the other side", leading me to believe that as on of the final 5 and the new, "prophet?" He has seen whats on the other side and knows that Kara will be there to meet him. He's been waiting for her for years, putting up with her complete obsession and dies for her because he loves and believes in her. She could never give him the love that he deserved back because her destiny wasn't complete. Once she heard the song and Jumped them to the real earth, Her soul became at peace. She finally has the chance to have the life she wanted, but was never allowed, to be with Anders together, on the other side.