They probably are some of the most popular anime characters out there not because of their strength, but because they are just darn charismatic and handsome (except Levi, sorry fans). Been meaning to write a comparison analysis of them for a while now so here goes!
ATTRACTIVENESS
Bearing in mind the period the respective anime are set in, one has to admit that all three characters are charismatic in their own ways. But I have to give in to Satoru Gojo. I mean, just look at him.
Unlimited Void (Manga CH15) Unlimited Void (Anime EP 7)
P.S. I ship GojoHime and Royai is canon.
Satoru Gojo > Roy Mustang > Levi Ackerman
COMBAT STRENGTH
This would be a tough fight. Anime fans may argue that it is not fair to compare strength across anime-verse, so let’s compare the strengths and weaknesses of each character.
Satoru Gojo
While we know that the Limitless technique involves the manipulation of space, we are unsure if what we have seen so far is the best of Gojo’s abilities since the 1.9 meters tall teacher is still sealed in the Prison Realm. Evaluating the scenes we have so far, we know that the man is literally untouchable because of Infinity unless there are Cursed Tools to nullify it or when he is inside a domain expansion. Still, Gojo’s Cursed Energy and Unlimited Void are probably strong enough to cancel out an opponent’s domain expansion as seen in his fight with Jogo.
Gojo has claimed that he can win full-Sukuna but we are unsure if the white-haired man is showing off and being cocky or simply stating the truth. We just have to see what Gege has in store for Gojo.
Roy Mustang
You don’t call someone a War Hero for no special reason. The Ishval War Hero’s flame alchemy is truly one destructive and in Pride’s own words, ‘problematic’. The Colonel is capable of turning anything into flames so long as he has an igniter and, well, oxygen. Roy’s biggest weakness is water but that proved not to be a major obstacle when he fought Lust. Not to mention, Roy is probably the strongest alchemist in the epilogue having gained the Truth (and thus the clapping alchemy) and his eyesight back.
Levi Ackerman
Levi is definitely the strongest human in Attack on Titan universe. Having read the manga, the only worthy opponents were just his uncle Kenny, and the Beast Titan. I would say the former is a tougher one considering they are both highly agile and they are fighting as humans as Levi does not have the upper-hand of leveraging on his small body frame to slaughter brainless titans’ neck. Rather, Levi is battling against a human and he has to depend on his wits, speed, and abilities to use weapons.
Levi’s fight with Zeke in the forest just left me laughing when the irritated and pissed Captain told Zeke that all he needed to do was read his damn book.
Even when he was heavily injured from the Thunder Spears accident (because Zeke has to move), Levi still possessed the combat abilities to fight against Eren. Nothing can stop this guy.
Factoring in the universe of each anime,
Gojo Satoru > Roy Mustang > Levi Ackerman
LEADERSHIP
Hands down The Flame Alchemist. These three fans’ favourite are certainly side characters and the sensei or mentor to the teenage main character.
Levi Ackerman
Levi, in my opinion, acts more like an adult companion to his Squad and just listens to commands by Commander Erwin. Very rarely do you see Levi taking commands. In the Female Titan arc, Levi refuses to decide a path for Eren as Levi has admitted himself that he does not know what will happen in either option. But you still have to remember that Levi made a very bold and selfless move by sacrificing Erwin for Armin’s life.
Satoru Gojo
Among the three contenders, Gojo is probably the worst leader, if at all. While he has a noble vision of changing the jujutsu system bottom-up, you don’t really see him lead his students or fellow colleagues in anything. Unlike his Kyoto counterpart Utahime Iori who is well-liked and respected by her students, few if not none of his students respect Gojo as their teacher but as a friend instead. Then again one might just say that Gojo need not lead anyone considering how he OP he is.
Roy Mustang
The youngest officer in Amestris is the definition of a leader. The raven-haired bachelor refuses to give up on Havoc despite his leg injuries and blatantly told his follower that he will wait for him once he becomes Fuhrer.


Episode 20
Roy Mustang > Levi Ackerman > Gojo Satoru
TEAMWORK
Definitely not Gojo. On a side note, it is rather lonely to be the only one up there. The combined power of Limitless technique and Six Eyes isolate Gojo from his peers, and Infinity literally prevents people from touching him, let alone know him on a more personal level. The birth of this blue-eyed sorcerer changed the jujutsu world with ransoms placed on his head the moment he was born.

Manga CH 75
While Gojo is easily the most annoying and arrogant character, even Pseudo-Geto and gang had better manners when they crossed the road, I don’t really blame Gojo for his attitude. Gojo carries such a heavy burden to eliminate Curses because he is the strongest. Everyone’s expectations of him are sky-high. After being forced to kill his best friend Geto, the responsibility falls on him alone.
From manga chapters
Roy Mustang
Roy prides himself as a strategist and don’t forget that even though the man was blind for the most part of the fight, Roy was planned the whole strategy to tackle the Promised Day, united the East and North battalion to fight against Central even when his squad were intentionally removed from him.

Credits: https://www.pinterest.co.uk/pin/860257966304701417/
Levi Ackerman
As written earlier, Levi is a loyal soldier and he does listen to Erwin’s commands dutifully even though these two had a shaky start before Vol 1 began (Levi actually wanted to kill Erwin but things happened and yeap). While strategic planning and tasks delegation are not exactly his forte, Levi makes sure that his squad does not fall and he supports them all the way.

Credits: https://attackontitan.fandom.com/wiki/Special_Operations_Squad_(Anime)
Roy Mustang > Levi Ackerman > Gojo Satoru
That’s how I feel about the characters. Surely I can do a more in-depth analysis of the characters or include more dimensions but maybe not for now. Let me know who is your favourite and why!