Nice concept!
I suspect the template you're drafting here is a bit too ambiguous. It also rubs up badly against
rule 101.1: to override a rule you need to directly contradict it, and I think this doesn't contradict the "you can only block one creature" restriction directly enough.
Current cards which can block multiple creatures do so by saying they can block additional creatures. I
think this card might need to say the following:
For each color, Town Guard can block an additional creature each combat if the additional creature is that color.
This lets me block any arbitrary creature (colored or colorless) plus an additional white creature, additional blue, etc. I could block three Battlewise Hoplites this way: one for my ordinary block, one for white, and one for blue. I could also block a colorless creature, an Agent of Masks, and a Battlewise Hoplite.
Legend wrote: ↑4 years ago
Is it capable of blocking Battlewise Hoplite creature and Agent of Masks creature, even though they share a color?
Whichever template you go with,
Muldrotha, the Gravetide's ruling helps us with a precedent in its rulings:
For example, you may cast an artifact creature card as your artifact card and cast another artifact creature card as your creature card.
This means we can say the Agent of Masks counts as the black blocker and the Battlewise Hoplite counts as the blue blocker. (Or we can count it as the white blocker and, in addition to those two, block a mono-blue creature.)