En (Н, н) is a letter of the Cyrillic alphabet. It represents the consonant /n/ unless followed by ь or any of the palatalizing vowels when it represents /nʲ/. It looks exactly like the Latin capital letter H, but it is derived from the Greek letter nu (Ν, ν).
Ironically, the letter I (И, и), which looks like a backwards N, derives from Η (eta) while the letter En (Н, н) derives from Greek Ν (nu) which looks like a backwards cyrillic И.