In the Mahabharata and Ramayana, there are many incidents in which people performed tapasya and obtained boons. Like Arjuna doing tapasya and obtaining something from Shiva. Once Arjuna and Krishna did tapasya in the night and they obtained boon from Shiva quickly. But for others tapasya had to be done for long time to obtain boons. Why different lengths?
There is also the incident of Parashurama doing tapasya and obtaining some boons.
Is it possible now for someone to do tapasya and obtain knowledge of fighting, like Arjuna and Parashurama? How long will it take for someone to obtain such knowledge by tapasya now? And what will that person be able to achieve? If such a person were to go against the armies of the entire present world, who will be victorious? Will doing tapasya also give one weapons?
In Mahabharata there are descriptions of various weapons, which can be invoked by mantras, is it possible to obtain knowledge of those weapons, who will be able to give someone those weapons in the present Yuga? And how would one go about doing that?
Is there any proof that tapasya actually works in Kali Yuga? I mean proof outside of Puranas, Ithihasas.