Toxic Behaviour, the phenomena where a person behaves in a way meant to intimidate or belittle another person, is an influential issue spreading across the virtual spaces that is online gaming communities. In this thesis we explore the possible correlations between Toxic Behaviour and game mechanics in online multi-player games by analyzing League of Legends (Riot Games, 2009), one of the most prominent online games currently dominating the market (Statista, 2014). We have analysed the game using a contemporary design framework used in the game industry accompanied by an ethnographical field study of the regular player base of League of Legends we have determined the most common reasons behind why these players tend to engage in Toxic Behaviour and if those reasons are connected to the game’s mechanics. Finally, we conceptualize plausible solutions based on our findings that hypothetically could decrease the amount of toxic player’s continuing engagement in Toxic Behaviour.