Death's Poker Fix (Deprecated) is a great mod to remove hitstops from Death's Poker. It can be applied to any of the three versions of the game, but is mostly compatible with the Greatsword version of Death's Poker.

It removes hitstops from all aspects of the game: the base attack, the attack that occurs on R1, the attack that occurs on R2, and the explosion that occurs on R3.

The only exception is the Ghostflame Ignition, which is the innate Ash of War for the Greatsword Death's Poker. This has hitstops for all of the aspects of its skill, including the base lingering flame, the explosion you can trigger by hitting R2 immediately after L2, and the blackflame trail created by hitting R1 immediately after an L2.

It also removes the hitstops from the other skills that use the Greatsword version of Death's Poker.