A Hybrid Approach To Build Automatic Team Composition In League of Legends Vinicios da Costa Oliveira * Bruno Jos ´ e Placides Matheus de Freitas Oliveira Baffa Alex Fernandes da Veiga Machado Instituto Federal de Educac ¸ ˜ ao, Ciˆ encia e Tecnologia do Sudeste de Minas Gerais, Departamento Acad ˆ emico da Ciˆ encia da Computac ¸ ˜ ao, Brasil ABSTRACT League of Legends is one of the most played games available in the market. The game had over 1.2 billion play hours from June 2011 thru July 2012, almost the double of the second place. We can as- sociate the success of this game with the growing eSports Market. In 2017, during the Mid-Season Invitational event, a Riot Games event held in Brazil, over 364 million viewers watched the tourna- ment. To reach success in this sport category, strategy and a good knowledge of the game is very important. Also, it is expected that the team mates and the coach define a good strategy while picking the characters, also called champions, which the team is going to play with. Our goal in this paper is to model a expert system to help the players decide which champion should be picked assum- ing that the champion is updated in the metagame and has a good synergy with the other champions. For that, the MinMax algorithm was used to model and create all possibilities of choosing champi- ons, and also a classification algorithm to evaluate each option and give them a grade to optimize the MinMax algorithm through alpha- beta pruning. The proposed modelling showed itself promising. Its application on eSports may result in the development of team com- positions never thought before in which may be very beneficial to the players. Keywords: League of Legends, Team Composition, eSports. 1 I NTRODUCTION League of Legends, also called LoL or League, is a recognized game from the MOBA (Multiplayer Online Battle Arena) genre. With a large amount of players around the world, it has increased its number of players over the last years. In 2012, the magazine Forbes [4], with data from DFC Intelligence and Xfire, titled the game as the most played game, with almost the double number of hours played than the second place. With many different game maps, League of Legends is always providing different ways to keep the players entertained. There are three fixed game maps, Summoners Rift, Howling Abyss and Twisted Treeline. Besides that, Riot Games, League of Legends’ developer, provides a rotative game mode in which a custom map become available to the players. The most played game map, also used for ranked games and tour- naments, Summoner’s Rift became the most popular map between the players. In this map, two teams with 5 players each, fight with each other in order to destroy the other team Nexus, the primary goal of the game. Summoner’s Rift is a squared map in which two bases is posi- tioned diagonally and in opposite sides. The space in between them is composed by three lanes, known as Top Lanes, Mid Lane and * e-mail: vinicompif@gmail.com Bottom Lane. The Top and the Bottom Lane tangentiate the map border, while the Middle Lane pass a diagonal line in between the bases. Also, between the lanes are fulfilled with a jungle with Neu- tral Monsters with special effects. Figure 1 contain a sketch of the map. The goal of the game is to destroy the enemy’s Nexus, a magi- cal structure located in the center of the base. This Nexus is pro- tected by three Inhibitors and eleven Turrets in which there are three Turrets on each lane and two closer to the Nexus. The Inhibitors avoid the other team to create Super Minions. Minions are small units spawned periodically by the Nexus to advance toward the en- emy’s base. They attack the enemy’s Minions, Turrets, Inhibitors and Champions on their way. With the growth of League of Legends and its application on the digital market, many eSports team started to invest in its competi- tive scenario. eSports can be understood as a type o sports in which is mediated by computer or video games [5]. Also, eSports is used to designate a competition, with teams managed and maintained by institutions, regional or worldwide. Figure 1: Summoner’s Rift Map by Riot Games In 2003, it was held the first electronic sport championship with over 150 thousand players all around the world. In 2004, the sec- ond event counted over a higher number, with almost 250 thousand participants [7]. Since then, this numbers grew up exorbitantly. In 2017, Brazil hosted the MSI Event (Mid-Season Invitational), one of the biggest championship of League of Legends, with over 365 million viewers [2]. In competitive games, every detail is important. In order to win the match, some strategies are prepared before the game in order to decrease the enemy’s chance to win. With infinite possibilities to combine characters, some compositions offer vantages over the others, and manage the task to pick champions, or characters, is SBC – Proceedings of SBGames 2017 | ISSN: 2179-2259 Computing Track – Short Papers XVI SBGames – Curitiba – PR – Brazil, November 2nd - 4th, 2017 630