SWTOR Nar Shaddaa (Empire) Red Mastery Datacron Location Guide

The Red Mastery Datacron increases your aptitude in combat, allowing you to do more damage. It will grant you Mastery +3 to your permanent stats along with codex: Galactic History 37: Freedon Nadd. There are 5 Datacrons in total located on the planet of Nar Shaddaa.
Note: You can collect them on either Imperial or Republic Side as they count towards the same achievement.

Datacrons are collectables scattered around the galaxy in Star Wars: The Old Republic. Each Datacron contributes towards your Legacy's passive stats permanently. Furthermore, they also provide interesting Lore and Codex Entries about the Old Republic era.

Starting coordinates: 1947, 2480.

This Datacron is located directly below the Taxi point in the Network Access area.

Jump off and land on the pipe directly below. Be sure to align your character with the pipe, so you don't risk gliding off.

From the pipe you can see a clickable taxi, but do not jump towards it. The distance is too far and you will die. Walk backwards instead and land on a ledge higher up than the taxi's platform.

Now you can jump down onto the taxi's platform, after you heal up.

Click the taxi and enjoy the ride.

The taxi will take you for a little bit of a spin, but will eventually land you on the small platform, where the Datacron is located.

This will grant you Mastery +3 to your permanent stats along with codex: Galactic History 37: Freedon Nadd.

This datacron holds unheard of power and knowledge collected by an ancient race. You access its power and discover writings which are clearly only one small piece of a massive galactic history:

Trained at the Jedi Temple on Ossus centuries after the Great Hyperspace War, Freedon Nadd was a powerful but temperamental Padawan. When denied promotion to the rank of Jedi Knight, the enraged Nadd struck down his Master. He left the Jedi and began to study the powers of the dark side.

Although Nadd learned much from a Sith holocron, he craved more. Nadd traveled to Yavin Four where he encountered the Massassi, savages who were once servants of the Sith Lord Naga Sadow. Nadd defeated them easily, and the awestruck Massassi took him to Sadow, who rested in a suspended animation chamber.

Unaware of the Sith Empire rebuilding itself on Dromund Kaas, Sadow believed Nadd was the acolyte he had been waiting for. But he underestimated Nadd's craving for power, and Nadd soon killed Sadow and left Yavin Four behind. Nadd settled on the distant world of Onderon, becoming a legendary tyrant.

Note: You can click the small communicator datapad next to the corpse that will teleport you back to the regular taxi point upstairs.