This Starscream is a clone of the original Starscream, created by Alpha-Q for the sole purpose of assassinating Optimus and Megatron. But Megatron overwhelmed Starscream, putting the clone under his control.
Starscream is capable of cloaking himself and has an F-22 Raptor for his alternate mode.
Starscream, unlike his predecessor, was loyal to Megatron's cause as right-hand man. Through Galvatron's power, Starscream 'evolved' into a full Transformer.