Bob is so damn incompetent.
Aside from rushing heedlessly into his death twice-over, even when he properly teamed up with mc he doesn't disengage properly when mc says they need to flee as the mage is incoming and it's better to let the goblin either bleed out, or ambush him next time when he is lacking an eye and arm and further weakened from lacking food.
And not only that, he instead just lets the super-wounded goblin actually slash him badly enough he instantly faints!
And when it's time to backstab the mage? He screams out his intentions first...
