So I was just wondering if anyone had any theories on why some goblins are pretty normal while some have special powers like Teppei's Iron Armor or the Freezing Breath of the bunny girl or even the acid-related abilities of someone named Acid Ruler that seems will appear in chapter 4.

Do you think it has anything to do with the personality of the human? or maybe its related to genes? Does it have to do with what you wish to be like Teppei wanting to protect people? Any other theories?