Kurotowa
Legend
What do you think? What about other items and powers? For example a Shield of Rejection might grant the Legendary Action of a Pushing Attack.
It's a clever reposing of existing game mechanics. It's a half decent way of reproducing a mythological item's effects in D&D. It also breaks the action economy over its knee and stomps on the pieces. So really, it's a question of what effect the DM wants.
Any DM using this should be clearly aware that they're introducing a massively powerful artifact that will significantly increase one PC's power and disrupt the usual turn order, possibly slowing combat down considerably. If they're okay with that, well, their game. Sometimes you want to hand game-breaking artifacts out to the entire party because you're deliberately aiming for that slightly gonzo "Deities and Demigods is our Monster Manual" campaign. Just, you know, eyes open and be aware of what you're doing. Giving legendary actions to PCs is not a small step.