How does the blue arrows on the defender work? What does it do

[meis]

No one knows about it, unfortunately. For me, the arrow thing is about the "tendency" of going up (red) or down (blue), my 2c. As for your question (if I understood it correctly), with blue arrow on the 3 CBs, they'll stay put on their line, marking the opponents, and not making silly forward runs. Again, my 2c.

Try having all your defenders and midfielders blued (is that a word? lol), and see for your yourself.