I'm getting a tattoo of song lyrics and I don't want to screw up the punctuation. The phrase is:
"No one is invincible
No one is immortal
These are the rules"
I feel like the safest bet would be a period between each. However, I think a comma between the first two lines, and then maybe a colon, semicolon, or dash between the latter two lines conveys the meaning better. I just don't know what that punctuation would be.