The Wizard: Starting by Scamming the Demon God

This is a magical world, in which many magical powers and races coexist with humans, including demons, evil gods, ancient gods, demons, fairies, and other magical beings. With the power bestowed upon them, humanity gradually ushered in its own era.
Among humanity, a group of crazed gamblers emerged, obsessed with making deals with wondrous beings…
They claimed...
Going all in is a form of wisdom!
They firmly believe...
No child cries every day, and no gambler loses every day!
They are...
Legendary Wizard!
Among the legendary wizards, Isaac is a special case. He doesn't consider himself a gambler. The reason is simple: gambling is not knowing the outcome, while knowing the outcome is investing!
A 1000% success rate, is that gambling?