The Brothers Strong
From Homestar Runner Wiki
The Brothers Strong is the collective term for the three brothers, Strong Bad, Strong Mad, and Strong Sad. The eldest of the brothers is Strong Mad, followed by Strong Bad, then Strong Sad. According to Strong Bad in the email flashback, The Cheat was taken in by The Brothers Strong when he was found in an egg filled with fishsticks.
The Strong Brothers' assumed surname is "Strong", since it is common to each of them. Even though the Homestar Runner body of work is an American-based cartoon, their family name is spoken before the individual's given name, a naming convention mistakenly labeled the Eastern order.
The nationality of the brothers is fairly ambiguous. Although Strong Bad often has a faint Mexican accent, his brothers have no sign of one. In Marshmallow's Last Stand and the Old Characters Page, the Brothers Strong are said to be from "parts unknown". In secret recipes, Strong Bad describes his childhood life in "Bumdumbourge" (a country near "Totalslava"), although this information is most likely false. Despite all this, it has been suggested numerous times that the brothers have lived in their current house in Free Country, USA throughout their lives (or at least since their childhood).
The brothers live together in a single house for unknown reasons. Generally, the brothers all hold each other in low esteem bordering on disdain. In particular, Strong Bad and Strong Mad think that Strong Sad is whiny and annoying, so they have been known to (more often than not) bully or reject him. However, there are times when they manage to get along on a positive note, such as their Decemberween photo together and their impromptu performance of "The Cheat is Not Dead" in the email caper. Overall, they seem to share a moderate sense of begrudging fraternity, if nothing else, for each other.
In the old Flash stuff it is mentioned the brothers once broke up, but later were together again. In the Old Characters Page it says that Strong Sad was disowned by his brothers, and in the Second Games Menu on the "Strong Libs" description, it is mentioned that The Brothers Chaps forced The Brothers Strong to reunite.
All of the Brothers Strong appear to be ambidextrous.