The color-related deckbuilding guidelines of Commander are centered round a particular attribute named ‘coloration id’
Color id is distinct from the colour of the cardboard itself, which is just decided by the mana value and color-defining talents
903.4. The Commander variant makes use of coloration id to find out what playing cards may be in a deck with a sure commander. The coloration id of a card is the colour or colours of any mana symbols in that card’s mana value or guidelines textual content, plus any colours outlined by its characteristic-defining talents (see rule 604.3) or coloration indicator (see rule 204).
Example: Bosh, Iron Golem is a legendary artifact creature with mana value {8} and the flexibility “{3}{R}, Sacrifice an artifact: Bosh, Iron Golem deals damage equal to the sacrificed artifact’s converted mana cost to any target.” Bosh’s coloration id is pink.903.4a Color id is established earlier than the sport begins.
903.4b Reminder textual content is ignored when figuring out a card’s coloration id. See rule 207.2.
903.4c The again face of a double-faced card (see rule 711) is included when figuring out a card’s coloration id. This is an exception to rule 711.4a.
Example: Civilized Scholar is the entrance face of a double-faced card with mana value {2}{U}. Homicidal Brute is the again face of that double-faced card and has a pink coloration indicator. The card’s coloration id is blue and pink.…
903.5c A card may be included in a Commander deck provided that each coloration in its coloration id can also be discovered within the coloration id of the deck’s commander.
Example: Wort, the Raidmother is a legendary creature with mana value {4}{R/G}{R/G}. Wort’s coloration id is pink and inexperienced. Each card in a Wort Commander deck should be solely pink, solely inexperienced, each pink and inexperienced, or haven’t any coloration. Each mana image within the mana value or guidelines textual content of a card on this deck should be solely pink, solely inexperienced, each pink and inexperienced, or haven’t any coloration.
What this implies is that if a mana image seems on a card, it’s a part of that card’s coloration id. It does not matter if the image is within the mana value, a capability value on the cardboard, or is produced by an impact of the cardboard. If the cardboard has guidelines that grant it different colours (like Transguild Courier) then it has these colours as nicely. The exception is that if that image seems in reminder textual content: Trinisphere nonetheless has a colorless id, and Crypt Ghast nonetheless has a mono-black coloration id.
If a card has a coloration id that features a coloration that isn’t a part of your commander’s coloration id, it can’t be added to your deck.
To tackle your particular examples:
- Shu Yun has a WUR coloration id.
- Cloudhearth Drake has a WU coloration id
- Covetous Urge has a UB coloration id
- Iron Myr has a R coloration id.
