Fullmetal Alchemist: Brotherhood is one of the most clever and philosophically deep shonen series there is, subverting a number of its tropes in favor of a story about war crimes, the price of ambition, the cycle of life and death, and much more. But it still has time for cool action scenes. Edward Elric, its protagonist, is a martial arts-oriented alchemist with two metal limbs, making him no ordinary fighter.
Who is he fighting? Father the homunculus is scheming to become a new god and sacrifice all of humanity to achieve that goal, and he's got seven minions to back him up. One of them is the lumbering Sloth, and although Ed and Sloth never actually fought for real in the story, what would happen if they did? Let's take a look.
Edward's Strengths & Weaknesses
First up, let's review what Edward Elric is capable of. He is no ordinary alchemist; even if it weren't for his automail right arm and left leg, he is still practically unique among the state alchemists of Amestris, because he does not need to use transmutation circles or arcane script. Since seeing the Truth when he performed human transmutation, he can perform alchemy just by clapping his hands together and touching a surface.
Because of this, Ed isn't weakened by having any transmutation circles corrupted or destroyed, and his knowledge of alchemy is rather deep. He can understand and break down just about anything, even sticks of dynamite, and rebuild that matter into something else. In battle, Ed may form barriers from stone, soil or concrete to protect himself, or elongate stone and brick surfaces into spikes or arms that can strike the opponent. Ed can also shatter the ground to throw his enemies off-balance.
In addition, Ed is a highly mobile martial artist, having been trained by Izumi Curtis, another alchemist who has seen the Truth. That, combined with Ed's short stature, makes him a difficult target to hit. He can handle even trained assassins in ordinary fist-fights (such as Lan Fan, one of prince Ling Yao's bodyguards).
As for weaknesses, Ed is highly vulnerable if his automail arm is destroyed, since he cannot perform alchemy if he can't clap his hands together (such as when he lost his first fight to Scar). Ed is also vulnerable to taking direct damage since he has no body armor and limited stamina and endurance. Getting hit just a few times puts him in a bad position, while regular stab wounds or gunshots can quickly bring him down. That's why he relies on alchemy barriers and evasion to avoid taking damage. Still, he can tire rather quickly, as his first fight with Greed the homunculus showed.
Sloth's Strengths & Weaknesses
As one of the largest homunculi, Sloth has enormous brawn to match. He can handle the mighty Major Alex Armstrong in combat and can easily lift large, heavy objects and toss them without any clear difficulty. In addition, Sloth is extremely durable, being able to shrug off bullets and only slow down a little when hit by a battle tank's shells. He is persistent, too: able to regenerate after taking a nasty hit from an alchemy spike and keep fighting as though nothing even happened. His ability to restore destroyed flesh is due to his Philosopher's Stone, which is packed with many souls despite its size.
In combat, Sloth uses straightforward attacks to wear his enemies down, and he sometimes uses the chains on his wrists to snare his enemies or tie them up against a pillar or tree. If necessary, he can use bursts of extreme speed, moving faster than the eye can see while also having enough momentum to smash down walls.
Sloth's weaknesses range from his fairly slow gait (when not rushing) and his dim-witted nature. He is not terribly clever, nor does he think ahead; he simply attacks a target when he sees one, choosing the most obvious methods to attack. He also has no ranged techniques, setting him apart from Lust and Wrath.
Edward Vs. Sloth: A Battle Of Attrition
If the two did clash, Edward will have the advantage early, being able to use his superior martial arts and his small size to avoid the worst of Sloth's attacks. But don't expect this battle to go the way you might think. Sloth could try to grab Ed or throw objects at him (or even use trees as clubs), but Ed could avoid those attacks and deliver counterattacks with spikes formed from the ground. Edward could also try to punch and kick Sloth, but that would do no damage, so alchemy attacks would be best. Ed would likely start wearing down Sloth's Philosopher's Stone this way, keeping it up as long as he can.
Sloth's laziness initially manifests as a reluctance to use his true power, but as the fight might drag on, Sloth's aversion to work could change to "let's end this quickly and stop fighting." He'd finally get serious and use his charge attack, taking Ed by total surprise. Sloth can't aim well, and Edward can put up barriers, but even then, Sloth would be sure to put Ed on the defensive and land a blow sooner or later. The moment he did, Ed would slow down, and Sloth could snare him with his chains and grab him. Then, Sloth could crush him, winning the battle of attrition.