Gordon Freeman

He has great skill in using handguns, shotguns, rocket launchers, and also have the ability to carry all of them and move around with no effort. Fighting and destroying unknown organisms who came from a place other than Earth, he also had shown skill in taking out the trained soldiers from the army and assassins working directly for the government with ease. Lastly, he went to a different dimension through a portal, broke through a line of various and a large number of aliens, then exterminated the head of those aliens(with a crowbar). He did this all in 4 days without rest and without sleep.

Next, he showed unbelievable skills of breaking into [The Combine] that conquered Earth in 7 hours and ruled it for 20 years, ended Nova Prospekt, and along with the aid of the resistance he razed [City 17]'s Citadel into dust and rubble.

All Gordon Freeman had was the HEV suit he earned from working in [BLACK MESA], the knowledge and experience from 'Hazard Course'(more like a fire drill for people working in a dangerous laboratory…), weapons he rarely used in his life, weapons that were created most recently, and a crowbar. Either than that, Gordon Freeman is a completely normal human being with no particular physical attributes. He is just a scientist. But despite that fact, he had shown a jaw-wrenching record of his accomplishments.

In summary, excluding the time when he was in the black void, he has the ability to not rest, keep on running, and keep on fighting. In other words, after going to work for [BLACK MESA] he annihilated an unknown alien force in 4 to 5 days, which is an accomplishment when considering that the resistance couldn't do ward off the Xen for 20 years. Even with his HEV suit and medkits that may have reduced his exhaustion and hunger, considering that he did that with no sleep, points out that Gordon Freeman is indeed something more than a human.

WEAKNESS: Without his HEV suit, Gordon Freeman is bad at any physical activities and he has very bad eyesight.

Isaac Clarke

Isaac Clarke is a normal man; thus, he has no record of having formal military training nor any sort of such training in any area. Also, there is no record or evidence that he had remodeled his body by using enhancing drugs or with an implanted machine. Thus, he has no special record of anything except for being a talented engineer. However, other evidence suggest otherwise.

Although his Standard Engineer RIG suit provided a bit of assistance in Isaac's physical strength, he was seen multiples of times in clothes where it was impossible for Isaac to wear any mechanic gadget to help him with his muscular strength, and in that state, Isaac Clarke performed to obliterate a Necromorph in a melee fight. This shows that he has exceeded most humans in physical strength. Such examples are… after tearing off a Lurker from him, which managed to latch onto him, away from his body he kicks it reducing it into a bloody paste; after slamming down an Infector down onto the floor before it penetrated his forehead, he ripped the muzzle by grabbing and tearing it; he drop kicked a Reaper before it tore his head or crushing its head with his bare hands and hurling it away from him. Even if Necromorphs are made from dead flesh that decayed for a while, an average person cannot possibly give severe damage to their limbs. Even when considering their weak body structure due to the decay of flesh into the equation of a Necromorph's durability, when thinking of the facts that mutated Necromorphs are able to withstand the heat of about or over 200 Fahrenheit and well below 32 Fahrenheit, and able to obtain skins akin to sharp blades that are able to cut up a person, it is logical to come to a conclusion that their durability would be more than just that of a decaying flesh and stronger than any average person.

On top of bypassing their durability with brute strength, Isaac Clarke has an extreme mental capacity as he was able to keep his mind sane even with dementia's constant interference. However, it is certain that he obtained at least a few traumas from the ordeal(fuck you Marker).

WEAKNESS: For some bizarre reason, he is weak against other human beings in physical terms. Also, he is easily manipulated by others.

Master Chief

His real name is John with his last name unknown.

Living in one of the UNSC's colony planets, [Eriadnus II], at the age of six, John was selected to be a participator of the SPARTAN-II Program in 2523. Unknown to him and his family about this fact, John was abducted along with 74 children and immediately became part of the navy. John, with his inborn leadership, led the other 74 and went through harsh training. Later, in the age of 14, he already obtained the body of an 18-year-old Olympic athlete and graduated with top honors from the Naval Academy.

With official training from a very young age, and possessing extreme luck, John-117 a.k.a Master Chief received every single medal(except for the prisoner of war medal) and this was even before the war with the Covenant Empire. During the war, the Spartans with Master Chief in the lead showed such progress for the UNSC that those of the Covenant started to religiously fear and spite Master Chief and his men. Thus, they even gave the Spartans the moniker of 'Demon'. This moniker is quite appropriate for Master Chief for him, technically all on his own, faced the army of the Covenant Empire and nearly reduced their numbers into zero. This action of Master Chief brought him many praises for the distinguishing military service, but Master Chief strives to set new outrageous records and even constantly breaking each record that he had made.

Although he is a soldier by heart and soul, he has undoubtedly learned and possesses enough knowledge of engineering and physics. He even showed extreme ability in mathematics in the gym while he was working out. Not realizing that he grew stronger, he thought there was something wrong with the gravity converter, and he calculated the gravity in the gym inside his head. At that event, John was only 14 years old.

WEAKNESS: Unlike his superior inborn luck, he has a massive jinx. Any vehicle that he rides somehow gets into a massive explosion or crashes. Whether it is a large battleship or a small carrier, it always faces destruction.

"..."

"GODDAMMIT, I TRUSTED YOU! FUCK YOU… AND FUCK YOUR MARKER!"

"Wake me when you need me"

.

.

.

One is silent, one is bitter, and one is ready for anything.

Run Xen before Freeman strikes you down with his crowbar. Run Necromorphs before Clarke stomps on your limbless corpse. Run Covenant before John-117 wreck havoc on your fleet. Run anybody, who decides to go against these three.

…

…

…

"How dare they defy the words of the Mondosia Kingdom! Go and bring them to me so I can teach them the consequences of crossing my orders!"

"These humans are the heroes… let the first unit with our finest warriors go and exterminate them!"

And there just happens to be some dumb organisms who decided to do that.