Oh, ohhh my poor vv...
There's one tiny scene in Showdown that always facinates me. After RGBY were all killed in front of TSC's eyes, his reaction was very interesting.
He did not charge at TDL blindly in grief and rage, he did not break down crying for his friends, he did not dwell on his friends' deaths at all. Instead, he turned to TCO immediately.
When he saw Chosen was surrounded by the swarm of Virabots, he still reached out a hand towards Chosen, then promptly got pierced in the back by Dark's virablades.
For me, this tiny detail made Second different from those typical fearless, hotheaded anime protagonists. This scene alone made Second a fleshed out, realistic character more than anything else in the entire season.
Yes, of course he grieved for his friends' death, but at that very moment, the fear for his own life surpassed everything else. He saw that powerful monster brutally murdered all his friends, and he knew he's going to be next. So he reached out to the only person he knew that could save him, and made a desperate plea:
"Please, help me. I don't wanna die."
Second was many things. He was a talented animator, an insatiable learner, a brave leader, a seasoned warrior. But at that very moment, on the brink of real, permanent death, he was just a scared child calling someone, anyone, for help.
And that made his conscious decision to protect Chosen all the more powerful, because it shows how brave Second really is. He knew his chance against Dark was minimal, he was scared, terrified even, but he still chose to put himself between Chosen and Dark, just because it was the right thing to do.
And that is true bravery. Bravery doesn't mean the absence of fear, it means feeling the fear, but choose to do it anyway.