One of Kaido’s attacks was named after Yamantaka, who is a Buddhist figure, appearing prominently wherever esoteric practices and beliefs are prominent (not only in the Vajrayana lineages!).
Yamantaka is a member of the so-called Wisdom Kings, also called Fierce/Wrathful Deities. Their role is to show a more fierce demeanour, which is more appropriate for certain lessons or just more appealing to some people. They usually are described as “wrathful emanations” of Bodhisattvas – wholesome beings on the stage to Buddhahood, who focus their energy to help all other beings reach enlightenment as well. At least according to the Mahayana teachings.
However, despite being closely related, there are some differences between them. Where a Bodhisattva would calmly explain that you need to look left and right before crossing the road, a Wisdom King would yank you by the collar to get off the damn road. Where Bodhisattvas are associated with the Lotus flowers, pure and clean, the Wisdom Kings are associated with the roots and murky waters they grow in. Bodhisattvas dwell in their Pure Lands and stand on a lotus, while Wisdom Kings have a lotus on the top of their heads, they dwell and wade through the murk.
Yamantaka personally is associated with death, wrath and ceasing ignorance. He is said to be the wrathful emanation of Manjushri – Bodhisattva of wisdom, typically portrayed as a young male with flaming sword. His name literally means “annihilator of Death”, for there are several stories about him defeating the god of death, Yama. However one must remember that this is not only literal death.
Death in Buddhism is very closely related to ignorance. To be ignorant is to be dead. To vanquish death is to become aware. And this is finally where Kaido’s attack name bears its importance: the incredibly heavy, domineering, direct hit comes right around the time Kaido chides Luffy for relying on the awe-inspiring power of his awakened devil fruit alone.
There is much more to the world of One Piece than brute strength or devil fruits by themselves. Luffy, ever ignorant and not really knowing what is going on, tries as hard as he can to fully harness the powers of his awakened Devil Fruit, essentially trying to brute force a solution. Only for Kaido to effortlessly smash him down, using an attack named after the very “Destroyer of Ignorance” to boot (if we equate death to ignorance, as we should here).
*by V1z3l