I can relate to what yer sayin'. I've encountered a few individuals such as the one ye've witnessed yerself sir. For example, one experience I had was back when I ran the role-play of Project Psychosis and one of the members would often boast via OOC-wise on how his character could easily slaughter mine when he's never even met my character via IC-wise (who happened to be Hatred; AKA The Puppeteer). His character was more bulkier in mass and could easily loom over Hatred for, I admit, Hate was a lithe fellow when he was still alive. However, I find it a bit amusin' as to how users such as the one I've experienced immediately perceive those smaller than they to be weaker in all aspects.
This is, obviously, not true for every character has her/his own strong points and weaknesses. I'll use a common example as to what I'm implyin'. Those heavier in weight and taller in height tend to be more dependent on their strength and willpower while those more diminutive and petite are dependent on agility and stealth. Of course, this does not apply to everyone. It is a bit brash for one to think that the bigger they are, the more immune she/he is to others.
Many have heard the sayin', "The bigger they are, the harder they fall", aye? While there is some truth to said quote, when it comes to the vast variety of role-play, this statement will not always be so precise.
I know this due to Vespian's recent encounter with Cyniue Vahlok (who is role-played by the user: avarigriffin). Cyniue is a lilliputian thing, five times smaller than Vespian himself. However, due to her agility and quick tactics, she is able to subdue and even confuse Vespian into a disadvantage. Yeah, she might not have the strength to virtually kill him, but killin' is not the only way to defeat an opponent, aye?
To wrap up my ramblin', I'll merely post another quote below that'll hopefully give a pointer or two to users who commence with an action such as this:
"Never judge a book by its cover."