Thunderwing is one of the largest Decepticons; so big in fact that his alternate mode is a B-52 Stratofortress. Despite this, he isn't stupid. To him, big is another word for fear causing, and in his case, he's right.
In B-52 mode, Thunderwing is capable of high speed flight and drops fusion explosives. In robot mode, one of his engines converts into a Plasma Cannon, capable of destroying a tank in a single shot, and even severly wounding another transformer. However, what he likes best is to smash things with his massive titanium (or whatever) fists.
His main companion is Artilleron. While Artilleron lobs high explosives from afar, Thunderwing tends to get in close and demolish anything in sight. Together, they are wanted for the perpetration of the Cyris Fields massacre, a battle which only Lockdown survived. They joined Megatron and 'friends' because of their similar outlook; only the strong survive.
Thunderwing now acts as an enforcer, demolishing anything that stands in his bosses way (people, robots, cities, entire planets, you get the idea).