Quintilagonist
Yes. Buck was the Protagonist.
The protagonist.
Quadragonist
protagonist
protagonist
protagonist
The Fifth.
DOG
Protagonist
Usually the medical term for the fifth toe is fifth toe. You could also call it the fifth digit of the foot, or the fifth pedal digit. The layman's term for the fifth toe is the pinky toe.
You could call it the fifth finger, fifth digit, or digiti minimi.
One fifth of a gram is typically called 0.2 grams.