Invincible from the Moment I Summoned a Demon

Luo Fan is reborn into a world where dragon-type beasts reign supreme. Summon the Flame Lord and become possessed by a demon, doubling your power. Summon the Death Witch and raise the dead, commanding an army of tens of millions of skeletons with a wave of your hand. Summon an undead bone dragon, immortal and indestructible, growing stronger every time it dies! Form contracts with dragon maidens and divine dragons, gaining the favor of Heaven and Earth. Every summon and contract brings unexpected rewards: the Demon Refining Pot, the Rumble-Rumble Fruit, the Dragon-Slaying Spear...