Hanzo, Spirit Seer

[Buddha and Demon, Good and Evil, Ice and Fire, Yin and Yang, Two Sides of One Being + An Unusual Leveling Method + Otherworldly Demon King Reborn on Blue Star + Not Invincible + No System + Unraveling a Thousand-Year Mystery]

Twenty years ago, a dimensional passage connected Blue Star to another world. Blue Star's scientists and a demon emperor from the magical realm joined forces to create weapons using technology and magic, defeating the demon king from the other world. But they never expected the demon king to be reborn in the body of Yi Yang, a good-for-nothing on Blue Star. Using his strange half-Buddha, half-demon abilities, Yi Yang begins an endless path of leveling up. As he grows stronger, he uncovers a thousand-year-old mystery from ancient times and prevents a world-ending catastrophe.