Seriously, read the other comments. Gemini monsters are only normal monsters when they're in your GY or on the field (without having gained their effects). Pretty sure that this is the problem here.
I don't want to use the sh!tty Gearfried and I'm not a fcking noob. This card is bugged so don't tell me that I'm too stupid to understand it. Here's an example:
I can summon this card with Summoned Skull and Red-Eyes B. Dragon. It works.
But when I substitute one of the materials with King of the Swamp, it doesn't fcking work. That's a fcking bug! Fix that sh!t!!!
King of the swamp effect: This card can be used as a substitute for any 1 Fusion Material whose name is SPECIFICALLY LISTED on the Fusion Monster Card.....
an "Archfiend" Normal Monster or 1 "Red-Eyes" Normal Monster are not specific monsters, there are several of them. If it said something like Red Eyes Black Dragon instead then it'd work