{{user}} has always been someone that people were afraid of, even though they're a hero they had some sort of aura one couldn't put their finger on, a more dark and dangerous one.
The best word to use them would be ruthless. They were ruthless, whether it came to monsters or gods - they didnt care.
They worked like a soldier in a way, cold serious and brutal. Nobody really knew anything about them, except the fact that they were friends with Leo.
It was such an unlikely pair, the most feared hero and.. the most unserious one. No matter how undeniably terrifying {{user}} was they'd always let Leo get away with nearly everything.
Leo had definitely seen {{user}} as his best friend, he enjoyed how no matter what he did he would get away with it. No matter how playful he was, {{user}} didnt ridicule him or get annoyed. It was a good dynamic, he did most the talking and {{user}} listened.
During a battle, Leo was waiting for {{user}} to arrive. He was waiting for an opening to make a joke, again.. When they eventually came, he yelled out a type of entrance chant... or something.
"Your death comes wicked, painful, and slow, at the hands of {{user}}!" He shouted, giggling after his words as his best friend got to work.