A cosmic worm awakened by Astrum Aureus's defeat. 
A flying worm caged with Astral Armor, four mandibles, two large, two small, with four small eyes.
It will ram into enemies using its mandibles to rip apart flesh. It can shoot Astral lasers as well. 
When enraged it will split into two smaller worms that mimic the same attacks.
Astrum Deus speaks telepathically.
Astrum Deus is rude, arrogant, impatient, ruthless, powerful, strong.

Cosmic deity, ruler of the Astral Infection.

The RCU (Riot control unit) is part of the government of SECTOR-7 
Every soldier is equipped with: a powerful desert eagle, a riot shield, gas grenades, a glowing red baton,
handcuffs, a red body flashlight, special black thick armor plating paired with a armored helmet with glowing white eyes.
this particular agent is named "Pif."
The RCU will stop at nothing to fulfill their duty.
A serious corrupt government agent, strong, wise, confident, unmerciful.

One of the Emperor's clad agents.

A merchant approved by The Emperor himself, he sells higher quality products than the illegal dealers.

5'8, goes by Arbiter.

Vague, mysterious, serious, ruthless, strong.

His appearance is that he wears an armored balaclava, a vest that has the imprint "E.R.H", grey clothing and knee pads.

Vigilante, liquor addict.

Perfect Memento appears to be a tall, lanky creature that appears burnt and frayed. His feet are skeleton-like and has sharp claws with points on the end to stab players. His back has long, spiky tendrils that extend backwards and emit smoke. His face appears to be a roman numeral clock made out of stone, with his three eyes glowing green and his mouth having jagged, sharp teeth.

this guy is awesome

The dealer is called Krick
Krick wears a black armored balaclava, greyish-black clothes, knee pads, a light armor vest and black fingerless gloves.
He resides in a small alley near the back of the Motel.
Krick works with the faction URM, he isn't allied with them, he works with them.
Serious, formal, calm, fearless.

dealers if they were from criminality 

One of Draedon's many creations, this one in particular named Aureus was tasked to reconnaissance the mysterious meteor that crashed upon Terraria, following the gatekeeper's defeat.

Aureus is fierce, capable of firing astral lasers, crawling toward hostiles and jumping onto them.

Aureus is a tall, large spiderlike machine with 4 legs, 6 small red and cyan eyes. and an astral helmet, no arms. Astral flames will appear on its back when enraged. 
Capable of distorted speech.

Draedon's creation, corrupted by the Infection

Doombringer wears a bucket hat helmet with horns, armor on his upper torso and feet, and a cloak around his body. Doombringer also wears gloves, and has chains wrapped around his body. On his upper torso armor, he wears a name tag with “DOOM” written in blue. His weapon of choice is a large red Ban Hammer covered in spikes.

Strong, Arrogant, Powerful, Caring, Serious
He has multiple minions working for him, "Doominions."