You can use this card with "Black Pendant" in order to inflict 500 damage to your opponent.
Cards like "Skill Drain" can remove this card's effect.
An excellent combo is done with "Butterfly Dagger - Elma", combined with a Spell Counter card. When "Elma" is destroyed by "Gearfried", it goes back to the hand by its own effect. This is used to activate "Elma" an infinite amount of times. Applicable cards include "Royal Magical Library" for infinite card drawing, and "Magical Marionette" for infinite attack and ability to clear your opponent's monsters.
By using "Gearfried the Iron Knight" with "Butterfly Dagger - Elma" and "Spell Absorption", if your opponent cannot stop the activation of "Spell Absorption", you can obtain as many life points by re-using "Butterfly Dagger" when it is destroyed. By adding "Fire Princess" into this combo, you can continue to increase your life points and deal damage to your opponent all at the same time, for a potential OTK.