Sechel was a non-Force-sensitive male Pureblood Sith who served as an advisor and envoy of the Dark Councilor Darth Nyriss of the reconstituted Sith Empire, and previously served in the Imperial Intelligence. Despite not being Force-sensitive, his intelligence and highly developed survival skills compensated for this and his underwhelming stature, which allowed him to rise high in Sith society.
Within Sith society purebloods that didn't have a connection to the Force where seen as lesser, even being called things such as an 'abomination', as Scourge commented on.
Nothing is known about his life as a child since this is never brought up in the Revan Novel. However, he was previously an agent in Imperial Intelligence and had many skills from this such as Slicing. He had a job outside of being advisor to Darth Nyriss; He worked freelance - being paid credits to find certain people, and was usually found doing this business in the Nexus Room Cantina where he had contacts, such as Larvit, who directed customers his way. He also owned an apartment somewhere in Kaas City.
Sechel is first seen escorting Lord Scourge to Darth Nyriss' stronghold. The two encountered two Mercenaries, to which Sechel 'chases' them off, before taking Scourge to the Stronghold by Speeder. They are met by Murtog, Nyriss' Head of security, and Sechel is asked, if this was the 'real Scourge'. Murtog denies them entry and after a brief interrogation by Scourge, Sechel tells him it wasn't fully Nyriss' idea to invite him, and was actually a suggestion by the Emperor - which was basically an order. The two Mercenaries from before show up again seemingly here on an assassination attempt on Darth Nyriss. Sechel cowers in the corner, miraculously not getting shot. Scourge defeats the two; managing to get one to surrender. Murtog appears, killing the last mercenary and allowing them inside.
Sechel also shows off his extensive knowledge on the different artifacts in Nyriss' possession.
Darth Nyriss sends Sechel and Scourge on a Mission to Hallion to find a lead to the assassination attempts; since Sechel managed to salvage data from a sabotaged droid that attempted to kill Darth Nyriss, that linked back to the Uxiol Droid Manufacturing plant on Hallion.
The two manage to sneak into the plant, only encountering a few patrol drones Scourge swiftly took care of; but when it came to getting into the records room, the code Sechel had wouldn't work and so Scourge used his lightsaber to slice through the controls - but in doing so, triggered the security alarm. Scourge threw Sechel into the Records room while he took care of the droids, which included some assault droids. Scourge had almost died to the droids, but was saved by Sechel triggering the emergency shut down.
Sechel hadn't expected Scourge to survive, but mentions they didn't have much time to escape from the shutdown destabilizing the plants Trivium generator. Both narrowly escaped the worst of the explosion, but where still badly injured.
This even made Scourge even more suspicious of Sechel's 'true' intentions.
Sechels data from the Uxiol Droid Manufacturing plant led them to a separatist cell on Bosthirda; where Nyriss assigned Sechel, Scourge, Murtog and Nyriss' troops to eliminate them and retrieve their data.
Once there, Scourge ordered Sechel and Murtog to stay back while he clears the area, but they willfully disobeyed the order and rushed in so Sechel could get the data before the separatists wiped any possible leads they had. Scourge was visibly angered by this, but Sechel showed his more cunning side here, not feeling intimidated by the Sith Lord.
The Data Sechel retrieved from this lead to them discovering they had an affiliation to the Dark Council member, Darth Xedrix; a known rival of Nyriss'.
After Lord Scourge had retuned from eliminating the Dark council traitor Darth Xedrix; he wanted answers for some things Xedrix had told him, and so went to interrogate Sechel - the one thing he'd been wanting to do for a while at this point.
The Sith had entered Sechel's room while he was sleeping and covered the advisor's mouth while holding a knife to him: demanding for all the answers if he wanted to survive, and so Sechel told him some of the answers he wanted - but not before having both his tendrils cut off. Nyriss eventually appeared saying how she would end Scourge if he harmed Sechel anymore.
After Revans' capture and imprisonment in Nyriss's stronghold on Dromund Kaas, Meetra Surik adventured to Nathema where she found T3-M4 and a holorecording of Scourge and Nyriss carrying Revan to their ship. This is what ends her up on Dromund Kaas, and making a deal with Larvit - who directs her to Sechel in the Nexus Room Cantina. She askes Sechel to find and set up a meeting with Scourge, not knowing the two know each other already. Sechel was able to charge extra for this meeting because of the fact Scourge was a Sith lord.
After Scourge met up with Meetra, Resulting in Murtog's death; they team up, agreeing on taking action against the Emperor - but Scourge needed to prove he was on Meetra's side, and so went to get all the intel on all Dark Council members that where apart of the Nathema conspiracy from the one person he knew would have it: Sechel.
He did this by luring Sechel into a trap, asking the human Slave at Nexus Room to send a message to Sechel, saying Murtog needed to meet with him. Soon after, Scourge followed Sechel through Kaas City, and to Sechel's apartment - where he watched Sechel enter the apartment, and then entered himself. Finding Sechel's apartment he entered and started to yet again interrogate Sechel, asking for the files Sechel was keeping of the Dark council's conspiracy.
Eventually Sechel gives in and leads Scourge to a small closet in the back of the apartment, which held a small safe that contained a blaster and some disks containing the files Scourge wanted - and Sechel handed them over to him.
Now seeing Sechel as a liability to his mission, he strangled the pureblood commenting on how he wanted their last moments to be 'close and personal'.