No. They're just in fantasy and would fare horrible in actual battle. You want a soldier who can work with others, keep his emotions in check and know WHEN to use violence instead of being violent.
Violent and emotionally unstable individuals are bad at morale, dont follow orders, and would sooner kill his own team then himself before getting anything useful done. Doesn't matter if you're OP as an individual, getting ganked on by a team of weaker but competent troops usually wins out 9/10 times. >tl;dr POWER OF FRIENDSHIP WINS AGAIN