"Y" are the consonants in Sky Lynx. "Y" can function as either a vowel (e.g. fly, sky, guy) or consonant (e.g. yellow, yet, Deployers).
"Y" is actually a letter from the Greek alphabet (the letter Upsilon), not the Classical Roman alphabet. "Y" is found in Greek words like ῠ̔πέρ (hyper), meaning "above" (or SVPER in Latin). The Romans used their letter "I" (e.g. MERCVRIVS = Mercury). Around the 5th or 6th Century CE, some Roman officials started using Upsilon but only when writing Greek words. But even then, Upsilon was approximated with the letter V (U in the Modern Roman alphabet). So "hyper" would've been written as HVPER.