Shen seems like a good brother, I doubt that he came back simply for Cole, it's not impossible, but it's much more likely that Zara, like the lovesick idiot she is, convinced Briar to go and get Cole, and worried about his two brothers, Shen had no choice but to go along
Touching on the topic now, Zara is a dumb son of a bitch. Cole is nothing but a cocky, arrogant bastard, who uses his strength on anyone who contradicts him, while at the same time being the biggest coward in the world, not fighting against people stronger than him, and even knowing this, Zara is still in love with him! I hope they die
If my brother Brian stays alive at the end, it's all good