
阿良々木暦
Also known as: Arararagi, Koyomin, Koyokoyo, Devil Boy, Kind Monster Sir, Monstieur
Height: 165 cm A third year high school student who is close to failing every class except math. He is a laid-back person whose only real friend at school is Tsubasa Hanekawa. Due to events prior to Kizumonogatari and Bakemonogatari, Koyomi avoided having friends and seemed to have lost faith and trust in people and himself.
Description from AniList, spoilers removed.

Bakemonogatari
Main · 2009 · TV · ★ 8.2

Nisemonogatari
Main · 2012 · TV · ★ 7.9

Monogatari Series Second Season
Main · 2013 · TV · ★ 8.8

Kizumonogatari Part 1: Tekketsu
Main · 2016 · MOVIE · ★ 8.3

Nekomonogatari Black
Main · 2012 · TV · ★ 7.7

Kizumonogatari Part 3: Reiketsu
Main · 2017 · MOVIE · ★ 8.7

Kizumonogatari Part 2: Nekketsu
Main · 2016 · MOVIE · ★ 8.5

Owarimonogatari
Main · 2015 · TV · ★ 8.5

Owarimonogatari Second Season
Main · 2017 · TV · ★ 8.9

Hanamonogatari
Supporting · 2014 · TV · ★ 7.8