Spirit-Pokemon:  
Spirit-Pokemon come from Spirit Gems given specifically to God-kings, Disciples of the God-king, and followers of the God King.
 
Spirit-Pokemon were originally the Poké-Gods of the Old World. Semi-legendary Pokemon to be exact. They lived among the Legendaries and other Pokemon during the day n’ age, however, the Spirit-Pokemon unfortunately had to go through the harsh effects of the Great Pokemon War. The Spirit-Pokemon fought against opposing Pokemon, unfortunately, opposing forces became too overwhelming for the Spirit-Pokemon and they had to retreat further into their Homeland. With forces about to come down onto them, the Pokemon used special Spirit Gems to keep them save and away from attacking forces. They hid away in their gemstones till the day that Takengrin Endmmar was the one to become a new God-king.
 
Takengrin Endmmar (me :P), after becoming a God King, got his personal Spirit-Pokemon Giratina in the episode titled “The Legendary Spirit-Pokemon of Old”. Where Adagio, and the rest of Takengrin’s wives got their Spirit-Pokemon in the same episode. Towards the end of the episode, Takengrin and his wives used their Spirit-Pokemon to fend off Team Rocket from stealing Pokemon from the sanctuary the God/Goddess gems were held in.
 
In the episode “The Spirit-Mons of Insanity”, the squad helped the Elements of Insanity get their Spirit-Pokemon. During the episode, the Hyperdeath Baryonyx tries to stop the Elements of Insanity from getting their Mons. List of what their Spirit-Pokemon are:  
Pinkies Cupcake:Mega Tauros and Mega Primape  
Brutalight Sparkle: Ultra Scizor and Phantom Darkrai  
Rainbine Dash: Mega Magnezone and Mega Zebstrika  
Rarifruit: Mega Haunter and Mega Purugly  
Apple Pills: Mega Rampardos and Ultra Kangaskhan  
Magic Mare:Mega Hoopa and Shadow Silvally  
Dinamodo: Mega Tyrantrum and Ultra Areodactyl  
Painset Shimmercakes: Mega Hoopa Unbound and a dark Silvally  
Fluttershout: a Ultra Glalie and Mega Exploud
 
Towards the end of the episode, Twimodo and Kamodo got their Spirit-Pokemon:  
Xerneas and Yveltal
 
Marionette Snowtrap got her Spirit-Pokemon, an Ultra Gengar and Banette, during the Super Pony Squad Halloween special titled “An Ultra Haunting”
 
Derpigun is the only EoI member to not have a Spirit-Pokemon. She believes the way she behaves she probably couldn’t even control a Spirit-Pokemon. Since then Derpigun is the only Elements of Insanity member to not upgrade from being a Drowned.