Is this for a game? I do like the use of the xylophone though.
At around 0:50, the strings need to be louder. For the most part, very amping, could be used as a battle theme. If this is meant to be a more epic piece in accordance with your description, it needs a bit more darker influence to it. Where's that "temptation?" It's poppy and strong, but not exactly dark enough to speak of a fight between brothers.