In conjunction with his powers, the shape of his head and pink hair resembles a mushroom, with what appears to be a face mask on his eyes, and black beard at his chin. He also wore a regal armor with a violet cape that covers his right side, shoulderpads, orange pants, fluffy shoes, and a weasel-skin scarf on his left shoulder.
Overall, Musshuru has a resemblance with his younger brother and late father, but unlike the former, he is tall and thin, and unlike the latter, he is more peculiar in overall appearance.
Musshuru is a cruel and arrogant man, as he violently defeated Luffy while mocking Chopper's attacks as he easily avoided them all. He also cared little for his subordinates and comrades, as he released a massive wave of poisonous spores that infected Chess and Kuromarimo, while showing no remorse when they collapsed in pain. He is somewhat battle-hungry, as he decided to entertain himself by fighting a defiant Luffy while telling Wapol to make the preparations for retaking the kingdom.
Like his brother, he has an odd speech quirk. Where Wapol calls people "kaba" instead of "baka", he calls everyone "Kabayarou", which means "Hippo-head". He also ends a lot of his sentences with "oi". Like many characters in One Piece, he has a unique laughter style: "Mushushushu", a pun on his own name.
Unlike his younger brother, Musshuru is a much more physical fighter. He possesses both incredible agility and fighting capability. He is capable of moving at speeds that could rival CP9's Soru technique. He is able to execute physical blows such as devastating punches that can smash through a castle spire with great ease. Combined with his Devil Fruit powers, Musshuru is quite a formidable opponent to deal with.
Musshuru ate the Noko Noko no Mi, a Paramecia-class Devil Fruit that gives him the power to release and control poisonous spores from his body. This ability of his is dangerous as the spores emitted from his body are fatal, and enough to destroy the population of Drum Island. He has crafted several peculiar ways of manipulating these spores. The spores can also be used non-poisonously, as several of his attacks did not poison his opponents on impact.
Though the poison is deadly, it has an antidote to it, and can easily be neutralized by fire.
After an incident when he released his spores several years ago, he was exiled from Drum to the Land of Fire, where his spores were nullified by the flame. As Blackbeard invaded Drum, Wapol left to recover his brother hoping his power could assist him in defeating Blackbeard. However, after he left he wishes to use Musshuru's spores to kill off all the people of Drum replacing them with his soldiers.
Thus he accompanies Wapol back to Drum Island. Wapol and Musshuru begin climbing the mountain, eventually being joined by Wapol's henchmen, Chess and Kuromarimo. Eventually, Wapol and Musshuru reach the castle, intending to take back Drum Island. Chopper and Sanji fight against Chess and Kuromarimo. Wapol, using the powers of his Baku Baku no Mi, attempts to shoot Hiriluk's flag off the top of the castle. Luffy protects the flag and starts to fight Musshuru, whose spores knock out Chess and Kuromarimo. He fights Luffy, at first evenly match against him, then managing to gain the upper hand by his speed and by poisoning him with his spores. Chopper tries to fight back, but he is defeated, too. Before Musshuru can give the final blow he stopped by the arrival of the rest of the Straw Hats. Musshuru is shot and set on fire by Usopp while Robin quickly administers the antidote to Musshuru's poison to Luffy. Luffy then uses Gear Second allowing him to keep up with and ultimately dominate Musshuru by using Jet Bazooka and crashing him into the castle's highest tower.
Wapol escapes into the castle and eats Musshuru along with the Bliking Cannon, fuses into a hybrid form with the intention of firing a poison bomb to annihilate everyone in Drum. However, Chopper uses Arm Point which launches him into the roof. Despite managing to fire the bomb, it is destroyed by the Straw Hats before it can explode. Luffy then defeats him and sends him flying away from the island with Gear Third's Gigant Pistol. Some of Musshuru's poisonous spores drift down, but Franky incinerates them with Fresh Fire.