Am I missing something here?

[Josh Has Worms]

I apparently cannot use the Meteor Dragon Red-Eyes Impact as a fusion material with the Claw of Hermos to summon the Red-Eyes Black Dragon Sword. I am not sure why.

The Impact card is dragon type. The sword only states dragon type and Claw of Hermos as a requirement.

[Josh Has Worms]

It looks like it may just not be letting you send cards from your hand, despite saying that you can send them from the field or your hand...

[Eliza Thornberry]

Just tested in EDOPro, which tends to be correct with rulings, and it works as intended, you can pitch Meteor Dragon Red-Eyes Impact to The Claw of Hermos to summon the sword.

Are you still able to activate the card and just have to send another card to the GY or does it not give you the option to activate it at all? If it's the former, it's definitely a bug. If it's the latter, it's possible that you activated another card effect that locks you out of using The Claw of Hermos. Notable examples include Red-Eyes Fusion, which will lock you out of special summons for the rest of the turn.

[Josh Has Worms]

Originally posted by Lily <3:

Just tested in EDOPro, which tends to be correct with rulings, and it works as intended, you can pitch Meteor Dragon Red-Eyes Impact to The Claw of Hermos to summon the sword.

Are you still able to activate the card and just have to send another card to the GY or does it not give you the option to activate it at all? If it's the former, it's definitely a bug. If it's the latter, it's possible that you activated another card effect that locks you out of using The Claw of Hermos. Notable examples include Red-Eyes Fusion, which will lock you out of special summons for the rest of the turn.

Yep, the former. I can activate it but it forces me to use field monsters instead of field OR hand. If I have no field, it lets me use hand. Super weird.

Thank you for testing it!

[Josh Has Worms]

Keeper of Dragon Magic is also broken. The secondary effect to reveal a fusion monster and summon one of its materials does not work. This game has a LOT of bugged cards...

[Veni_Vidi_Vici]

Well upon my own testing with the Claw of Hermos I had no issues and could choose from my hand or field to summon Red-Eyes Black Dragon Sword.

Originally posted by Josh Has Worms:

Keeper of Dragon Magic is also broken. The secondary effect to reveal a fusion monster and summon one of its materials does not work. This game has a LOT of bugged cards...

What fusion monster and material monster were you attempting to do this with?

[Josh Has Worms]

Originally posted by Veni_Vidi_Vici:

Well upon my own testing with the Claw of Hermos I had no issues and could choose from my hand or field to summon Red-Eyes Black Dragon Sword.

Originally posted by Josh Has Worms:

Keeper of Dragon Magic is also broken. The secondary effect to reveal a fusion monster and summon one of its materials does not work. This game has a LOT of bugged cards...

What fusion monster and material monster were you attempting to do this with?

Meteor Dragon Red-Eyes Impact typically. I also noticed it sometimes works.

[Veni_Vidi_Vici]

Originally posted by Josh Has Worms:

Meteor Dragon Red-Eyes Impact typically. I also noticed it sometimes works.

Well for Keeper of Dragon Magic in order to even get the option to activate the effect you have to have a monster in your graveyard that is specifically listed on one of your fusion monsters. For example Red-Eyes Slash Dragon has "Red-Eyes B. Dragon" + 1 Warrior Monster. You can activate the effect if you have a Red-Eyes B. Dragon in your graveyard but not if you just have any warrior monster.

Keeper of Dragon Magic wording is "whose name is specifically listed". This means any fusion monsters with only generic or even archetype specific material requirements are completely invisible to Keeper. It has to be a specific name.