I remember reading an Iron Fist comic in the late 1970s where Iron Fist (Danny Rand) squares off against a similarly-clad opponent. This enemy has a similar mask and skin-tight outfit as I.F., though his outfit is blue (IIRC). He also has a tattoo on his chest, but it is different than I.F.'s
Iron Fist channels the power of his Iron Fist to his enemy's delight, who grasps him and holds him against his chest tattoo. Fist says/thinks something about his Chi being drained, and collapse unconscious. The villain leaves him alive, but says something about how he wants the Iron Fist power for himself.
I don't know if this guy was a one-off, or a recurring foe (didn't read many Iron Fist comics).
Time/Date of Publication Late 70s to 1980, no later, I think.