Let us do some holistic analysis of Malgus's power progression:-
When Malgus was a Sith apprentice:-
- Achieved fame in the Sith Empire for his impressive talents and potential.
- Was regarded as the "greatest embodiment of the dark side" by Satele Shan. According to her, she had participated in hundreds of sparring sessions but nothing was enough in the Jedi Order's training sessions to prepare her for Malgus's ferocity.
- Tanked and tore right through a Starship engine hurled towards him like a missile.
- Cut down Jedi Master Kao Cen Darach in a duel after tapping into his powerful anger (in the zone moment).*
*Kao Cen Darach:
Darach was a remarkably skilled duelist, Jedi Order's battlemaster (master of all combat forms), and able to duel his opponents with both a Saberstaff and a normal lightsaber wielding with great precision and speed. While simultaneously dueling Malgus and his Sith Master, he cut down the latter with ease.
Canonically, it is difficult to become proficient in Jedi dueling arts with use of a Saberstaff but Darach reached a whole new level with his skills.
Depiction: http://www.swtor.com/info/media/wallpapers/return-4
Kao Cen Darach was powerful in the ways of the Force; he was able to send Malgus's Sith Master (a Sith Inquisitor) packing across the open arena with a single blast of power. In addition, he was able to hurl large and heavy objects (e.g. starship engine) like missiles towards his targets with high accuracy. Furthermore, he was also proficient at deflecting powerful bursts of Sith lightning.
It shall be kept in mind that Sith Inquisitor (Masters) are canonically formidable in the ways of the Force and it is not easy to overcome one in single combat.
Conclusion: At this point, Malgus have already demonstrated the capability to overwhelm opponents of Dooku's caliber.
When Malgus was a Sith Lord:-
- Defeated/disarmed several remarkably skilled and powerful opponents in single combat. Once defeated two Jedi in duel even in heavily wounded condition (one Jedi was a powerhouse).*
- Prevented the portion of debris from two buildings which collapsed around him from crushing him beneath with his raw power in the Force, throwing apart the debris in various directions.
- Tanked direct missiles hits.
- Endured "cliff shattering" Force powers.
- Hurled heavy objects (including a large boudler) like missiles towards his targets with high accuracy.
- Once collapsed a gigantic structure and nearly vaporized some beings in a fit of his powerful rage, unleashing incredibly potent raw energy at that moment.
- Cut a swath through Jedi formations in battlefields, killing many Jedi in the process.
- Inflicted heavy structural damage to the Jedi Temple with his raw power in the Force.
- Once unleashed a wave of energy with enough pressure to move a large aircraft from its position, killing large number of opponents with it simultaneously.
- Achieved oneness with the dark side.
*Satele Shan:
Satele shan was an absolute master of the Force, possessed prodigious Force powers and a formidable duelist by all accounts. She could destroy objects weighing hundreds of tons with her raw power in the Force, possessed advanced shatterpoint abilities and was extraordinarily proficient in the defensive ways of the Force (she could prevent even lightsabers from impaling her with bare hands). She also possessed great knowledge of esoteric talents such as; she once killed 3 Sith adepts simultaneously with a mysterious power; could even survive in space by forming a protection bubble around her; and once blew apart a group of extremely dangerous hex droids from inside out with gesture. Shan was a stuff of legends by all accounts.
This is the impression satele left on another remarkably talented Force-user:
From Star Wars: The Old Republic: Fatal Alliance:The Grand Master had impressed with more than her telekinetic and telepathic skills. Her speed and decisiveness in combat were unbelievable—but she never once made a sound. Her face was calm, almost serene, as she slashed and hacked through the hexes. There was a tranquillity about her, almost a blissfulness, that spoke of an intimacy with violence Ax had not expected.
To the Sith, violence was an art form. To Master Satele, it seemed like life itself.
That didn't marry at all well with what Ax knew about the Jedi. Weren't they emotionless, self-righteous hypocrites who fought only when it suited their interests? Didn't they disdain passion and preach powerlessness to all who would listen and obey?
For the first time, Ax saw that there could be strength in serenity, and steel beneath stillness.
*Mysterious powerhouse:
After from severely injured in a set-back he suffered on Aldeeran from one of his confrontations; while he had disarmed Satele Shan in a duel, a legendary Republic trooper interfered at the crucial moment, costing him the duel. However, even after enduring a "cliff-shattering" power, Malgus quickly recovered from near-death situation with his power in the Force and he was not done with the Jedi yet.
Malgus found another Jedi on his way and landed near his position. This Jedi was not an ordinary one either; in a remarkable display of power, he collapsed two buildings around the position of Malgus in an effort to crush him beneath the rubble. However, Malgus held his own by preventing a portion of heavy debris aloft with his power in the Force and then channeled that power even more effectively, throwing apart the debris in different directions away from him. Malgus then leapt from the mountain of rubble to confront this Jedi and eventually defeated him with his extraordinary dark powers. In the same confrontation, Malgus killed another ally of the mysterious powerhouse, who attempted to ambush him, by choking him to death.
In this confrontation, Malgus also demonstrated the capability to detect Force-users who could mask their presence with the Force. The ally of the mysterious Jedi had actually masked his presence in the Force to prevent the Sith Lord from detecting him but this talent did not work in his favor either.
NOTE: This mysterious powerhouse demonstrated Darth Vader level Force abilities and he still failed to overcome Malgus.
*Ven Zallow:
Zallow was a powerful Jedi, regarded as the most formidable Jedi stationed on Coruscant amidst some other powerhouses such as Bengel Morr, Usma, Orgus Din and Kellian Jaro at the time of Sacking of Coruscant.
Zallow honed his talents in the Force to make himself an extremely capable duelist; he was able to create a blur of precision and speed with his dueling prowess; could perceive incoming blaster-fire with great clarity and deflect it back to it source without even paying attention to the source; cut down some battle-hardened elite Sith warriors as fodder in the heat of combat; even blitzed two battle-hardened elite Sith warriors at one point in the heat of the battle. Furthermore, Zallow outgunned Lord Adraas with relative ease when the Sith Lord landed near him to attempt to eliminate him.
Malgus regarded only Zallow as a worthy opponent for him inside the Jedi Temple among hundreds of other Jedi.
*Aryn Leener:
Aryn was an extraordinarily talented and powerful Force-user by all accounts. She acquired a position in the Jedi High Council as a Jedi Knight due to her remarkable talents (a rare occurrence in galactic history). She was also a remarkably skilled duelist.
Leener could physically move and react so fast in a burst of speed that even a millisecond would pass around like a minute to her during which she could perform multiple actions simultaneously. To normal eyes, she would appear to be a blur of motion, existing simultaneously in multiple places.
While dueling opponents, Leener would augment her physical attributes to extreme levels making it virtually impossible for her even exceptional duelists to strike her down with their martial skills.
Leener was prodigiously talented in the use of the Force, able to perceive her surroundings with great clarity and detail, augment her senses to perceive her surroundings on planetary scale, unleash overwhelming waves of energy with which she could collapse structures and overwhelm multiple Force-users simultaneously. Leener could also hurl large objects like missiles towards her targets; in one confrontation, Leener lifted 6 large objects (possibly vehicles) simultaneously and hurled them like missiles towards her targets. She was also proficient in the defensive aspects of the Force; in one confrontation, she deflected a powerful wave of energy with a gesture in such a way that she split it in two with one-half ending up topping some large seconds and other-half ending up overwhelming another Force-user. She could also disarm other Force-users with her telekinetic abilities with ease. At one point, she telekinetically took control of a Saber Throw attack aimed for her from Malgus, robbing him of its control in the process.
In addition, Leener survived a dive from the space onto the rooftop of one of the skyscrappers in Coruscant (from 50 km height) without the use of any parachute, using the Force in remarkable ways to slow down her descent from terminal velocity speeds and protecting herself and her companion in the process, preventing her and her companion's death upon landing on the building. On another occasion, Leener used her power to slow down the descent and cushion the landing of a dropship in which she was present.