Valdo Gollini, also known as Dark Might, is the main antagonist of Boku no Hero Academia the Movie 4: You're Next. He is the leader of the Gollini Family mafia.

Before altering his appearance with his Quirk, Valdo was a somewhat lean man with sunken green eyes, light stubble atop his lip, and black hair that was slicked back. Like most members of the Gollini Family mafia, he wore dark dress clothing, with his preference being a black blazer and vest, with dress undershirts and bowties. After taking over the family business, he is shown wearing a pure white tuxedo suit and dress shoes over his regular garb.

When taking on his Dark Might persona, he looks similar to a younger All Might in his empowered form when he possessed One For All, bearing an equally muscular physique and short blond hair that is swept backward, with two distinct tufts sticking above his head, leaning slightly to each side. There are a few differences; bushier eyebrows, straighter and thicker hair tufts, a tanner complexion, and a bigger, more hooked nose. Dark Might also retains his original eye color and markings compared to All Might's clear, blue eyes. He mainly wears a white tuxedo suit with black accents, white pants and dress shoes, a dark blue collar undershirt, a pale blue bow tie and handkerchief in his left pocket, and a bright red rose on his left lapel. He also wears eight golden rings, four on both fingers, but none on his thumbs, something that is consistent throughout all his costume changes.

In the past, Valdo was a ruthless mafia member in his family who always beared a sullen and dim expression. This ruthlessness did not exclude anyone, including his own father, who he gunned down point blank in his own office. Back then, Valdo was aware of All Might's accomplishments and strengths which he greatly admired. As his father pointed out though, Valdo did not see that All Might's strength was not what defined him, but rather his heroic will to help other people.

After becoming one of the most dangerous Villains in Europe, and sometime after All Might defeated All For One in their second battle, Valdo became heavily fixated on All Might and decided to dedicate his new purpose to becoming the new All Might.

Valdo/Dark Might's Quirk is "Alchemy", which allows him to transmute the matter of any non-living thing he touches. He can create fully functioning objects, buildings, weapons, and can even modify his appearance. Alchemy is also capable of changing the state of matter of an object completely into forms like glowing energy. Transformed objects can still be actively changed if Dark Might maintains contact with it, allowing him to create things like pitfalls and secret doors for him and others to access that can disappear without a trace. He can also do this to reverse and repair any damage his creations sustain if he wishes.

When Alchemy is boosted by "Overmodification", Alchemy's range expands significantly, allowing Dark Might to activate his Quirk without using his hands and create much larger and more complex structures and modifications. When applied to his disguise, this allows Dark Might to utilize variations of All Might's strongest Ultimate Moves, giving him a rapid flurry of powerful punches that rival those of All Might.