Pokémon Fusion Generation is a 2012 fangame developed using Pokémon Essentials.
Fusion Generation begins with the Champion of Hoenn, Brendan or May, arriving in Kanto to take on a second league challenge. Upon arriving they and their counterpart who also seeks Indigo League badges find out about a new craze sweeping the Kanto region: Pokémon Fusions, created by Bill.
Bill's invention proves to be controversial, and after distributing fused Pokémon to most of Kanto's gyms and offering one to the player - Charvee, Warvee, Eeveesaur, or Pikavee - Bill prepares to destroy his machine. But Bill's realization comes too late and the power of Pokémon Fusion has already fallen into the hands of foes from the past. Soon their mysterious leader has taken control of Indigo Plateau, and it will take a Pokémon Fusion master to stop them.
There were initially 102 unique Fusion species in Pokémon Fusion Generation and 2 more were added through updates, Rhydark (Rhydon + Zoroark) and Luvitar (Luvdisc + Tyranitar) bringing the total to 104.
The first Fusion you receive in the game is Pewter Gym Leader Brock's Herawoodo, a formidable combination of Heracross and Sudowoodo. The game's mascot is Pikavee, a fusion of Pikachu and Eevee which Bill owns and later evolves into Raicheon. Only fusions of Eevee are capable of evolution in this game.
Fusion Generation was released on November 11, 2012 having been in the works since 2004. Development of a sequel, Fusion Generation II began in 2013 with plans for a third entry after that. On June 26, 2014 as it neared completion attorneys representing Nintendo of America contacted the developer and brought an end to development of the series. It was the first Pokémon Essentials project to be targeted by Nintendo.