firt letter: Alast letter: Z
Q r s t u v w x y z
Probably "W". It was created sometime in the sixteenth century to replace uu, which was not a letter, but simply a couplet of letters. The "w" was most likely created to save space and time. The "uu"...
Ω (omega) is the last letter.
Ω/ω - 'Omega',