It's J's most important accessory. He rarely takes it off, and when he does he hides it - it's that valuable to him.
The hoodie is actually a symbiotic demon (affectionately named Loid by J as a kind of joke). It's essentially...well...a void, hence J's nickname, and he uses it to store various interesting and sharp pointy things for easy access and later use. Its sleeves can also extend to wrap around a target and hold them in place. I suggest you donít get caught in them because the openings of the sleeves are rimmed with shark-like teeth.
It get's its power from blood so, yes, the thing drinks blood - which is what the teeth are for. So I repeat, don't get caught in them! When it feeds, you'll see red 'veins' tracking through the sleeves up into the shoulders. Also, this act of feeding for some reason makes the wearer of the hoodie feel an intense sensation of pleasure...like, orgasm pleasure...Obviously, putting two and two together, if the hoodie hasn't eaten in a while it is significantly weakened...too bad J likes to keep it fed...
The hoodie can talk to people telepathically, but only if itís touching them. So yes, sometimes it does look like J is talking to himself when heís actually speaking with the hoodie. J also uses this ability as a weapon to psychologically torment people.
If a host applies their soul to it, the hoodie can use their barrowed power to change shape Ė wings, color, bullet-proof, black hole surface (if there is enough will power), etc. However, the more it is used, the less human the host becomes and the hoodie will eventually take over their souls and bodies, leaving a soulless shell. As long as the hood is drawn over the head, the hoodie will be able to remotely control the hostís entire body. Otherwise, it can only control the areas of the body it is touching, so mostly the torso and hands. In the dark, a controlled bodyís eyes will glow red (fun fact). The hoodie is lifeless and cannot talk or move on its own.
However, this little ability doesnít work on J because heís already dead, and his soul isnít technically in his body anymore. This infuriates the hoodie to no end and its constantly lamenting its inability to be in control. Thus, itís constantly trying to get other (living) people to steal it from J and put it on. Every time it tries to pull some trick on J he puts it through the wash cycle as punishment. It doesnít like the wash cycleÖ
J may be light and small - hell, you could probably easily throw the bastard - but he makes up for it in speed and agility. He can easily keep up with a freight train or even a taking off jet-plane. So good luck outrunning him. Good luck outgunning him too, because he'll just get right back up after he's healed. The more serious the injury, by the way, the faster J heals. So if you blow his head off with a shotgun he'll be right as rain in about a minute. Run him over with a train, and the regeneration is almost instantaneous.
In life, J was quiet skilled in hand-to-hand combat, and he still is. He prefers knives to guns nowadays, especially his scalpels, so be prepared to die by a thousand cuts instead of a bullet hole.
He's a master at creatively killing and torturing people too, so it would probably be in your best interests to do yourself in if you find yourself on the losing end of the stick. Somehow get rid of your body too, or he just might bring you back for fun.
Ghoul Child: a little ghoul girl that acts as J's primary assistant, and the creepiest little shit to walk in the good doctor's considerably dark shadow
Marco: head of the Gravediggers
Jeremy: a fellow demon who works as J's head of security at the hospital