I initially had my doubts, but now that I see the 5k damage, the 1k fp, the 10 def stat bonus, the range and no cooldown, the 5 second duration of no enemy invulnerability, I am 100% supportive of this new item’s immediate designation as the ability of the samuray.
However, I have one suggestion. Have it be a 8 radius circle, centered at the player, rather than a shot. I believe this would improve the balancing and make the samuray as a whole a decent choice for a class.