What does Minato's teleportation kunai say?
忍愛之剣 (にんあいのけん 又は しのびあいのけん)

Sword of Shinobi's Love

That image is not accurate. The person who drew the picture clearly didn't pay much attention to the characters. 

There is a YouTube video called "Did Naruto lose his six path sage mode" The cover photo has these four characters

Also, if you google these 4 characters, you will see there were a lot of people that have asked this question before