He is a leader
The Arsenal back line is prone to making errors. This is mainly due to the lack of leadership in the defence. Koscielny is not vocal and Mustafi is inconsistent and not a true leader. This often leads to Arsenal defenders losing the ball unnecessarily and switching off on occasions. With Koscielny out for six months due to an ACL injury, much of the burden of the team's leadership will fall on Sokratis
After wearing the captain's armband on various occasions for Borussia Dortmund as well as the Greece national team, Sokratis has experience of being the leader in the team. He is vocal and leads by example. With years of experience under his belt, Arsenal could finally get the leader they have been crying out for.
He will be vital in Arsenal's 2018/19 campaign as he will not only be the backbone of the team's defence but also a huge mentor to all the young players in the side. In Koscielny's absence, he will mostly play with a young centre half beside him and will have to put all his experience to use to achieve the best results for the team. However, seeing the Greek defender's mentality, there is no doubt he will take this challenge head on and help Unai Emery achieve success in his first season at Arsenal.