A: She's the main antagonist, but she has always been evil. She's trying to spell the word 'APOCALYPSE' to kill everyone. She also has a letter cloner. B: Exact same. C: Exact same except he gets kidnapped. D: A cool, calm and collected dude. He doesn't have a major role apart from 'looking cool'. E: A young, sweet letter. He may look like an equivalent of I, but he's actually the main protagonist of the series. F: Equivalent of G. G: A sweet, cheerful girl who is E's love interest. She joins the heroes. H: Exact same, except he actually has a much larger role. He joins the heroes, but he sadly dies in episode U. I: Exact same, except he gets saved. He doesn't join the heroes, however. J: Exact same. K: Exact same. L: Has the same design as Wario100's remastered Swedish L, but he doesn't die. Instead, A uses him to kill H in episode U, before she kidnaps him. M: A bashful letter. He doesn't join the heroes until episode X. N: Looks the same as the original N, but he is not the main protagonist, nor is he cowardly, nor does he own a gem. He is sort of the second equivalent of G. O: E's strong father. He immediately rushes in the cave in episode W to kill A, but he gets kidnapped himself. P: Exact same, except she gets kidnapped instead of dying. Q: Looks the same, but he doesn't have a gem. Instead, A kills him in his own episode. R: An absentminded letter. A kills him in his own episode, but he actually contains a powerful gem that E uses to kill A. S: Exact same. T: Equivalent of R except he doesn't get kidnapped. U: A bored letter. He doesn't do much in the series. V: A skilled fighter who is the X equivalent. He fights A, but he loses. He doesn't die, however, instead, he gets seriously injured. W: A hyperactive letter. He unfortunately dies after A bites him in half. X: A letter who gets around by doing cartwheels. He is very slow, however. Y: A tomboy. She attempts to make friends with A in her own episode, but she gets kidnapped. Z: Looks like Wario100's remastered Swedish Z, but they're not a main character.
Credits to the original owners for the sprites. Also, to be extremely original, I decided to not include a superhero team.