For example, In bleach there is a quincy who has a unique ability that allows him to calculate the perfect lethal dose (the amount that will cause death without fail)—of any substance he takes into his body (primarily by ingestion) and then raise or lower that value as he sees fit, inducing a lethal dosage of that substance in those around them. In order to facilitate the lethal dose, he needs to consume a great amount of whatever it is he wants to manipulate into his body. For example by consuming blood, he can decrease the lethal dosage of the blood in his opponent's body, thus making it fatal to them
And by using this ability, he basically forces his opponent to either continue fighting him while the blood inside them is poisoning them or force them to purposely lose blood in their body in order to bring down the lethal dose needed to keep them alive.

For example, if the person has 4l of blood in their body and the lethal dose needed to kill them is 2l, then that person would have to lose at least 2+ L of blood in order to not die from their own blood (which is now poisoning them). However, they now face the problem of dying from blood loss.
It just feels like one of the many reason the series feels stale and fans are moving away from it has to do in lack of innervated ideas. With other animes providing new hax, and interesting abilities to characters, changing the hair colour of established transformation and reusing past abilities is not going to cut it anymore.











