The Steel Finger is a combat skill highly popular among female heroes for unknown reasons. Even though the Steel Finger is a combat skill, it's uses do not pertain to combat 100% of the time, as seen below.
Levels 1-5: Only the tip of the pointer finger becomes steel and rigid. Very useful for cleaning one's nose, poking eyes, and other various things.
Levels 6-10: The entire finger becomes steel, which is useful for poking someone really hard and leaving a bruise. And cleaning one's nose.
Levels 11-15: The entire finger becomes steel, and can be formed into sharp and jagged edges. Very useful for poking holes into walls for spying and peeping. Be very careful when picking one's nose.
Levels 16-20: The finger can be shaped into a small knife, useful for assassinations, eating, picking one's teeth, and picking locks, but not noses.
Levels 21+: The finger becomes harder than diamond when used, sharper than any blade known to human and beast, and with proper force and placement, can bring down even the strongest of monsters and heroes with a single blow. Very useful for trimming nose hairs, according to some other heroes.