Starscream (known as Nightscream in the Japanese series) was recreated by Alpha Q with raw energon after been destroyed 10 years ago in the Armada series by Unicron. When recreated, he has no memory of the past.
Packaging by Hasbro. From the illustration on the packaging, Starscream is packed with some awesome weapons.
The Decepticons in the Energon series do not have the ability to powerlinx with each other like the Autobots but they have another feature called the Hyper Power Mode. In alternate mode, Starscream hyper power mode reveals the null ray cannon on its wing.
Starscream was later recaptured by Megatron where he reformat Starscream's spark to become his loyal soldier.
Starscream can also hold the weapons from Insecticon (which is also a Terrorcons in the series)
In robot mode, Starscream able to deploy the Hyper Power Mode where it reveals the powerful null ray cannon over his shoulder
The rifle and sword can combined to form a large energon blade to inflict more damage. Occasionally, the energon blade can be used as a shield by rotating it when under attack.
Here are the comparison between Starscream in the Armada series and when he was revived in the Energon series. Some similarity still exist such as the sword and the null ray cannon over his shoulder
The transformation manual from Takara, which I found more informative than Hasbro
StarScream bio data. There are a few unknown characteristics. In the series, he did not act as a second in command but earn a lot of Megatron's trust. His teleporting ability made him extremely fast for his enemy.