The many Quirks of My Hero Academia are incredibly diverse in their abilities. Some are defensive or passive, while others are geared toward offense, like Deku's One For All or Bakugo's Explosion. But others, like Sekijiro Kan (aka Pro Hero Vlad King) and his Quirk Blood Control, are surprisingly versatile on both fronts.
Class 1-B's homeroom teacher hasn't gotten nearly as much screen time as his counterpart Shota Aizawa, but fans might remember the Blood Hero's brief clash with a Dabi clone in Season 3, during which he used Blood Control to trap the clone for interrogation. As the name suggests, Vlad King is the master of blood, and his Quirk is not only great for offense and defense, it gives him superhuman survival capabilities too.
Blood Control allows Kan to freely manipulate his blood, even if it's outside of his body. If Kan's blood gets into the air, he can move it around like a thick mist, and the possibilities are many. Kan can spread the blood out to form a variety of constructs, from a sheet that can block paths or protect allies to spears and weapons to attack the enemy. And, as his fight with Dabi showed, Vlad King can also use his blood in its fluid state to bind opponents and harden it to keep them in place. Given Kan's pro status, it's likely that he can even more than that.
Blood Control is useful even beyond its ability to protect and attack. Pro Heroes are still human, meaning they all have weaknesses to exploit. One would think that blood loss is Vlad King's main weakness, but the Blood Hero handily eliminates via the very nature of his Quirk. If an enemy slashes or stabs him, then he will begin bleeding, sure, but that just means he has more tools to work with on the battlefield -- the blood isn't lost, it's freed.
Vlad King can recall any lost blood into his body at will, though he usually doesn't need to go that far in battle. Ordinarily, Vlad uses his costume to release blood on purpose to move it, and evidently, his blood sustains his body even outside of it. Otherwise, his Quirk would be fatal to use. Whether Vlad King releases his blood or a villain does, he's just as ready to keep fighting. Instead, his enemies must incapacitate him with blunt strikes, like a concussion, rather than trying to slice and dice a hero who can't bleed out.