Age: physically and mentally 12, has lived for 220 years though.
Height: Whatever is normal for a 12-year-old boy.
Weight: Very, very light. She weights almost nothing.
Eyes: Light Blue
Hair: Dark Brown

Medical Info: Eli is a vampire. In LTROI this is explained as a virus infection, where the virus has a bit of a life of its own. When infecting the body it builds up something that could be most easily explained as a second brain just above the heart, from where it controls the body's functions. The host is in control for almost all the time though, unless survival instinct kicks in and the virus takes over. Also important is the fact vampires aren't dead, and they never died. If a body with the vampire virus dies, the person would turn into something similar to a zombie instead of a vampire. Despite this, a vampire's heart just beats around 5 beats a minute and they don't need to breathe. Some specifics about the vampires are that:

• Sunlight and fire can kill them really easily. Stakes to just above the heart works too.
• They must drink human blood to survive, and the blood needs to be fresh. Sick blood tastes disgusting and drugs/Alcohol affects them as if they had taken it themselves.
• They can't enter any kind of building where people already are without being invited by somebody already inside it. This doesn't just apply to homes, since she needs to be invited to a cellar and a hospital in canon. Also once invited she can use that "door" as many times as she wants to. If she wants to enter the building from another door or opening she would need to get another invitation, though.
  
• Cats hate them with a PASSION. LTROI Vampires triggers some sort of primal fear in cats that makes the cats just want to kill them or at least run away.
• They heal incredibly fast, especially when newly fed.
• Vampires can see in the dark but not in complete darkness. Their pupils are like those of a cat.
• They can grow fangs at will and also claws and a kind of membrane that can work as very basic wings.
• They have a sense of hearing far superior to that of humans. Also, they are STRONG.
• There is no "vampire kiss". It's either someone nicely donating the blood and licking the wound (since the bite is infectious) or tearing up people's throats and aim for the jugular vein. In short; vampire bites hurt like hell.

 Not related to the vampirism is the fact that Eli is actually a castrated boy. Castrated as in, it all got cut off shortly before he was turned into a vampire. Unlike in the movie, the scar is really faint and it's mostly healed.

Physical traits: See Medical Info. I summed it all up there. Eli looks like a normal, but pretty, twelve-year-old. It can be a bit hard to tell her gender, but most people seems to settle for female.
What's Okay To Mention Around Him/Her: Anything o/ I can't think of anything that would be off-limits.
Abilities: Various vampire skills. I.e. can grow fangs, claws, bat-wings and see in the dark. Also superior hearing and strength and doesn't need to breathe and isn't bothered by the cold. She can also share her memories if she kisses someone.
Notes for the Psychics: Vampire!!!1 Since the vampire virus works like a separate brain-like entity, this would probably be what you'd first notice (It's actually sort of similar to the DDS cannibals). Eli's mind works like that of a twelve-year-old so you wouldn't be able to tell her actual age. Eli probably thinks a lot about Oskar. 
Hugging/Kissing/Other non-violent physical contact: Sure o/ Kissing might result in being invaded by very unpleasant memories, though.
Can I shapeshift/bodyswap/spit at/step on/etc?: Just ask!
Maim/Murder/Death: Most wounds heal, so go ahead. Since I know have an Oskar, ask us before you kill Eli. Oskar has enough serial killer potential as it is.
Cooking: … No.