As The error was carried out with the god Indra, he grants Hanuman a want that his overall body can be as robust as Indra's Vajra, Which his Vajra can also not harm him. In addition to Indra other gods have also granted him wishes: the God Agni granted Hanuman https://hanumantempleinadelaide.news.blog/2024/07/12/the-universal-appeal-of-lord-shanidev/