Evolution: William asked God for an RPG System, similar to Solo Leveling, making him stronger with each fight.

Soul Eye: A unique power he wished for God. Inspired by Jack the Ripper, from the anime Shuumatsu no Valkyrie. William's right eye has the ability to see people's emotions as colors. By looking into a person's "soul", William can discern their true intentions even by the slightest change in color.

Stealth: A Skill acquired through the RPG System. Stealth allows its user to physically blend in with the environment and hide all traces of their presence, becoming completely invisible. With only powerful users of Observation Haki being able to detect it, even if with some difficulty.

Rasaka's Iron Scales: A permanent effect, acquired by ingesting the Item "Purified Rasaka's Poison". Causing a 75% decrease in all physical damage he suffers.

Complete Immunity to Poison: Another permanent effect gained by ingesting the item "Purified Rasaka Poison". Making William completely immune to any type of poison.

Bloodlust: When angered, William is able to release a powerful bloodlust, thus managing to intimidate his opponents. Similar to Conqueror's Haki.

Assassin's Haki: A Haki unique to William. Similar to Conqueror's Haki, this Haki aims to intimidate his enemies. But at the same time, it causes those affected by it to feel an extremely powerful murderous intent emanating from William, causing them paralysis, among other effects.