The marks seem like tattoos, but they are smaller than that. They are microscopic and densely packed all over his body.
The marks aren't tattoos, actually. They are what makes up his body. They are the information of his Supreme law.
So anyone who sees him will be able to comprehend his Supreme law by observing his body. This is something that is common to every world god.
World gods can comprehend each other's Supreme law directly, but they don't do so because to comprehend the Supreme law of another is to start a fight with them.
Even if they don't retaliate when someone is trying to comprehend their Supreme law, that person must have a large and powerful mind to contain their existence. If they don't, then their existence will explode.
But if they retaliate by a little bit, anyone who comprehends their Supreme law can be overwritten from within as long as they comprehend enough of it.
