So I guess he could handle his power (without dying and all) with the help of the "spirit kings" power, well that's just a nice coincidence there. OK
SO in total Our mc has the power of
The strongest hero (his mama)
The strongest demon lord [with centuries stacked of power]
Trained by; said Hero, Strongest martial artist, The president of one of, if not the most, prevalent goods company (guessing) since mc knows of it even from the village he lives in, The last king known for his wisdom, and a omnipotent Slime sage that is already known for being all-knowing and powerful-----Not to mention he was on par with all these people and more at the age of 5
oh yeah
He's also the chosen hero by the spirit king
…...Why are all the isekai stories these days about harems and god level power pretty much right off the bat (though sometimes I enjoy these)