Replace faction.

The ID of the Wyvern doesn't process "blood"; all other creatures can use blood.
In my mod, I simply created three new creatures, named them Wyverns, and linked them to the Wyvern visual, and as a result, I got Wyverns with blood (but internally, they are not Wyverns) 😬

Please provide more details. Does your statement mean that this is a problem only with the specific ID of the Wyvern (formally, they have been banned from having Blood at the executable level)? But if you add any other ID instead of it, will it work, and can there be an "Orda" in which all its creatures will have "Blood"? Including T6.