What I admire about Nocturne's design is how its function reinforces the theme of the character himself, going so far as to evoke visceral emotional responses and actions in players themselves that make sense given the horror that Nocturne is supposed to represent.
Recently, when playing League of Legends, I have been playing Nocturne a lot.
As a Multiplayer Online Battle Arena, League of Legends concerns pitting players against one another in 5 vs. 5 matches on a three lane field of battle. Each lane contains turrets that need to be defended or assaulted by players, and at the beginning of the game, this is usually done by assigning two characters to the bottom lane, one to the middle lane, and one to the top lane. The final player is usually assigned the role of jungler (which is typically the role that the aforementioned Nocturne plays). While players in the three lanes battle to advance on one another’s towers, the jungler roams a neutral territory in between lanes, killing neutral monsters in order to level up and gain gold to buy items to empower himself. Additionally, the jungler’s job is to harass the lanes that are in contention by attempting to gank (that is, attempt to kill) opponents in a lane to give his teammates an advantage there.
Nocturne is a melee assassin, who has a wicked ability to initiate fights in the various lanes through an ability that allows him to streak nearly instantaneously to a single target from quite far away on the map and then to terrify them with another of his abilities (slowing their escape) before savagely attacking them with his claws.