Oh well in that case
Here's why the IRS might exist in the Magic realm:
We know that the word jeez exists in the magic realm meaning that not only did Jesus Christ exist but so did the Roman Empire
Thus we can assume that the Ottoman's and Byzantines also existed and thus the silk road as well
However dude to the fall of Constantinople in 1453 Europeans had to find another way to get to America
So obviously Colombus goes to the Americas and Western European arrive there ff a few years and you got the 13 colonies and this the United States
However we know that the US like them pockets FILLED with money
Pockets drenched pockets healthy type shit
which means taxes which means that there needs to be a central authority to check your tax forms and thus comes in the IRS