Gray is the 8th strongest wizard in Fairy Tail. Gray besides being a fulltime stripper is an amazing Ice wizard who always tries to fight for his comrades and always tries to move on from the past that keeps haunting him. His mentor Ur saved him from Deliora (one of the demons of Zeref) and used Iced Shell using her body as the ice to trap him. Gray also thinks he wasn't able to save Ultear his mentors daughter leaving Gray with serious personal luggage. Gray using these reasons to fight hard make him strive to win no matter what obstacles it might take making stronger and tougher everyday.
Gray uses a series of techniques including: Ice Make Cannon, Ice Make Shield, Ice Make Hammer, Ice make Lance, Ice Make Unlimited and can even form his blood into ice. Gray can also create fake copies of his body using the ice to trick the opponent and surprise them with an attack. Gray is an amazing ice wizard if I do say so myself.
In the Tartaros Arc. Gray comes face to face with one of the Nine Demon Gates of Tartaros who happens to use Ice Devil Slayer Magic. Before the battle Gray realizes he's not just a demon but also looks like his Father. After the demon took Gray away from everyone else the demon confessed that he was Silver Fullbuster Greats father and lied to Gray saying that he was just using the body to hide his true form Deliora. Gray terrified for a moment goes on a rampage but starts to feel like he's going to lose because nothing was working on Silver sense he uses Ice magic as well Gray thinks he has to do Iced Shell (at the same time thinking about all his friends and Juvia!) (What Ur did to Deliora) But tricks Silver by pretending to do Iced Shell and shoots a cannon into Silvers body. After admitting defeat Gray realizes that Silver is not Deliora but really his Father. Silver explains how he is a nacromancer (dead puppet) and all this time he has been trying to avenge Gray and his mother. Once Gray realizes the truth he cannot kill his father and end in a hug. Once Juvia defeated Keyes Silver also disappeared but gave Gray his Ice Devil Slayer Magic to once and for all the demon named END. Now as an Ice Devil Slayer Gray is possibly the strongest Ice Wizard out Fiore. I truly can't wait to see Gray become stringer than he already is.