Full-Time Mage: Starting with Gengar, selected for the National Tournament

Chu Ming transmigrated to a magical world and awakened the Elf Summoning System.
Each time a spirit is summoned, there is a chance that the summoner will awaken a corresponding magic-type ability based on the spirit's attributes and traits.
Meanwhile, the summoned spirits can also be leveled up by idling.
Whenever the elf's cultivation improves, it will give back to its master, Chu Ming, strengthening his physique and boosting his magical cultivation.
As Gengar (Ghost and Poison types) leveled up, so did the level of Gengar.
Chu Ming's progress in cultivating the Shadow and Poison arts also increased accordingly, progressing from the initial stage to the intermediate stage, advanced stage, super stage, and forbidden spells...
……
That day, they faced the invasion of the Dark King of the Underworld, the Emperor of Antarctica, and the Cold Moon-Eyed Demon God.
Level 200 Gigantamax Gengar, Gigantamax Charizard, Primal Kyogre, Gigantamax Rayquaza... a host of legendary Pokémon from the world's highest tier have appeared.
Standing high in the sky, Chu Ming felt the surging forbidden power within his body—the power of shadow, poison, fire, water, wind, and space—and couldn't help but hum a leisurely tune: "How lonely it is to be invincible~"