R (SPOILERS AHEAD, SCROLL DOWN AT YOUR OWN RISK) (if you don't know, "delfín" means "dolphin" in Spanish)
Credit to @wario100 for voicing E and I, @NycookieScratch for voicing D, and @NumberLoreTheSeries for voicing F. I voiced A, L, N, and R. Credit to @PhonicLover44 for the letter sprites and bases and @elithepidude for the gem sprites and bases. Punch/kick and dolphin sound effects from Quicksounds.com Slugging sound effect from Soundbible.com Inspired by Mike Salcedo's Alphabet Lore