I think I read this about a decade ago. Cartoonish, but decent, art style. The main protagonist was a very large fellow, caucasian I think, dark curly hair, kind of built like a football linebacker. In the first set of strips, he's out on a date with his girlfriend when someone ambushes him and hits him with a shovel. In the course of fending off the attacker, it becomes evident that he's unharmed, but that he developed purple armor plating where he was hit. He explains himself to his girlfriend, and we learn (I can't remember if he succeeds in hiding it from her) that he's a member of a school of people being trained to be superheroes. His roommate is a somewhat scatter-brained blond, either gay or bisexual, maybe with strong psychic powers involving him always knowing the right thing to say? He's a bit of a himbo, innocently callous. One of the other members of the school is a guy who can split himself into two copies. I remember there being a strip where they test either splitting or merging where only one is wearing a hat, and it causes the hat to tear into two pieces, the top and the brim. One of the recurring nemeses is, I think, a former teacher at the school, who gains access to a pyramid that gives him immense energy powers. The first time he shows up (I think after gaining the pyramid device), the students convince him that, with all of this power, there's no real challenge on Earth, and he rockets off to try to conquer space. I think I remember a later scene involving a school trip, maybe a crossover with another superhero webcomic, where they fight some kind of sea monster. I think there was another scene where the blond roommate winds up infiltrating a villain hideout, and he hooks up with a male bartender.
This sounds like Special School.
The first couple of strips match exactly to as you described.
The main character is Iain. Both his physique and powers are as you described.
Iain shares an apartment in the Reeve Residential block with Ruby and Manny. He's basically a nice guy; none too fast but with a respectable facility for information retention and retrieval. Iain had to give up a promising career in college football when his powers manifested.
When struck with sufficient force, Iain's bruising process is instantaneous and highly resilient - in effect, the struck area is immediately armoured.
And Iain's flatmate Manny matches as well.
Romantically, Manny can be seen stepping out with Karne, the cyborg bouncer from superhero hangout Club Jotunheim, but this has not stopped him coming on to anyone in pawing range.
Manny says what you want to hear. Or rather, he says what he knows will most likely provoke the desired reaction in you. In an unconscious process, he rapidly skims the subject's mind and analyses their response patterns, drawing a line between what he wants and how you think.