Martinez is a small demon.
I use him as a LB, and he hasn't disappointed me once. He runs down the pitch like a madman and with him being lengthy he also catches up to every striker (also Mbappé!).
He can literally win you most balls by just bullying the other player off the ball. Despite him being not that tall, he usually wins headers (even against taller players).
Really smooth dribbling for a defender
Winning nearly every header
Being a small demon or a nightmare
He's too cheap for how cracked he is