He is on each account rank 1 with 5 stars and queues up 4 accounts simultaneously. (For those not familiar with the format: if you lose a game you lose a star, if you win you gain a star, to go from rank 2 to rank 1 you need 5 stars. If you are rank 2 zero stars and you lose a game you drop back to rank 3 with 5 stars, etc ... once you get legend you will attain that ranking till the end of the month). Or in other words, he needs on each account 1 more win to become legend.

https://www.youtube.com/watch?v=1dzyzJxemi0