Press space or click to see the next letter. Α has A's design. Β has B's design. Γ has C's design. Δ has D's design. Ε has E's design. Ζ has G's design. Η has H's design. Θ has I's design. Ι has F's design. Κ has J's design. Λ has K's design, but isn't a bug and is male. Μ has M's design, but is gray and small. Ν has L's design. Ξ has M's design. Ο has N's design. Π has O's design. Ρ has P's design. Σ has Q's design. Τ has T's design. Υ has W's design. Φ has V's design. Χ has X's design. Ψ has Y's design. And Ω has Z's design. Ι is the villain because he wants to spell "Φίλοι" ("Friends" in Greek), by torturing and assaulting other letters. Back when he was a lowercase kid, he and ο got bullied by ν and π; as a prank, he decided to spell "κλανιά" ("fart" in Greek), causing the other letters to sneer at ν, except η, who instead takes a whiff at the fart and dies, turning into a ghost. To get revenge, ν and π push ι around until he spells "χάλια" ("crap" in Greek), making all of the letters (except ζ, ο, and ρ) to get mad at him and beat him up, to even κ breaking his teeth. Eventually, σ squirms into view and eats a question mark gem, and gains the ability to see into the future, then he tries to catch up with the other letters so he can warn them of what will happen in the future; meanwhile, ι, feeling dejected, goes into his lair while the letters spell "θύμα" at him ("victim" in Greek).
Credit to all. No, there is no U equivalent, so don't bother asking.