Half Eladrin generally looks like half-elves with tattoos on their skin. But if you better look you may easily find some differences.
First of all there're much taller than ordinary elf or half-elf because they usually are 5' or 6' tall. Then, they're the tattoos which often covers half eladrin's face, arms and other body parts.
There're big differences between half eladrin themselves. See, a half eladrin descendant from a firre will have red hairs and/or red eyes while a half eladrin descending from a shiere will surely have long, thin face and maybe gold or silver hairs. But, despite of this physical differences there's no differences in the half eladrin's capacities.

Half Eladrin tend to be determined and passionate. When they do something, they do it with all their heart. It's not surprising when an half eladrin fall in love in a first sight and spend all his life with this person. He may also decide to do something and leave all his friends, money and anything else to do it. A good example is a sod named Gycyren. The chant goes he abandons all his fortune (a jewelry in Sigil) and spent all his money to make a twenty years journey in the radiant plane with a wizard he engaged to this. When he was back, after twenty years, he was poor and alone but he achieves his project and realized his only dream. So berk if you see a half eladrin dreaming about something virtually impossible don't say it to him. They can be two results: he can laugh at you or attack you. These people can't stand insults.

Ability adjustments: Half Eladrin have a +1 bonus to Strength and Charisma and a -2 penalty to Constitution.

Special abilities: Half Eladrin have a +1 bonus to saving throws vs. cold, fire or gas and a +2 bonus vs. electricity. They also have a natural magic resistance of 5% and they're only surprised on a surprise throw of 1.
Once per day then can use the following spell like powers: heal light wounds, detect evil and comprehend languages. Half Eladrin also have 60' infravision.

Special hindrances: Half Eladrin are very vulnerable to cold wrought iron, like they eladrin parents. So they suffer a -2 penalty to their AC and their enemy has a +2 damage bonus. If the cold iron weapon is enchanted the magic cancel the proprieties of the blade.

Class options: Most of half eladrin are fighters but there are also wizards, priests, paladins, thief and rangers. If the half eladrin is a specialty priest he will probably choose the god of love, war or another chaotic good or neutral alignment. Specialty wizards can chose every magic school but invokers and wild magicians are the most common and necromancer the rarest. Half Eladrin can be also mutliclassed, as follow:
fighter/wizard, fighter/thief, fighter/priest, wizard/priest, and thief/wizard.

	Strength	Dexterity	Constitution	Intelligence	Wisdom	Charisma
Min/Max	7/18	8/18	6/18	9/18	9/18	13/18
Ability Adj.	+1	-	-2	-	-	+1

Aging effects

Middle age*	Old age**	Venerable age***
62	83	125

* -1 Str/Con , +1 Int/Wis
** -2 Str/Dex, +1 Con, +1 Wis
***  -1 Str/Dex/Con, +1 Int/Wis

Average Height and Weight

Height	Weight
Base	Modifier	Base	Modifier
65/63	+1d12	140/100	+4d12

Note: The height and weight of the character is defined be adding to the base (male/female) the rolled dice written on the modifier row. The weights are in pounds, the heights in inches.

Fighter	Ranger	Paladin	Wizard	Cleric	Druid	Thief	Bard
15	12	12	12	-	12	12	-

Single classed characters can rise two levels above these limits.

Ability adjustments for thieves

PP	OL	F/RT	MS	HS	DN	CW	LR
-	+5%	+5%	+15%	+5%	+10%	+5%	-

Physical traits

Bralani: silvery-white hairs, multicolored eyes, short (about 64-68 in) and stocky (+160 lb for male, +120 lb female)

Coure: very short ( 66 male, 64 female) and thin (about 145 lb for male, 105 female), various bright colors

Firre: red hairs, red eyes , tall (+72/+69 in) and stocky (+170/+130 lb)

Ghaele: tall (+72/+69 in) and athletic (+160/+120 lb), pearly eyes, opalescent aura

Noviere: green, blue or golden skin, blue-green or pale blond hairs, deep-sea eyes

Shiere: very tall (+74/+71 in) and thin (150/110 lb), long faces and arms, golden or silver hairs

Tulani: very tall (+74/+71 in) an svelte (170/130 lb), shining face, natural beauty and grace

(NOTE: Not all of the characteristics are present in every Half Eladrin)

Alignment

Common alignment	Rare alignment	Very rare alignment	Forbidden alignment
CG,CN,NG	N,LG	CE,NE,LN	LE

Common alignment – These alignment are the standard one for PC and NPC

Rare alignment – These alignment are rare, which mean than the PC with it are rare to.

Very rare alignment – PC with those alignment are unique ore close to. This means that a PC has a personality that doesn't match with the one of his kind. He won't by accepted in the social structure of his race.

Forbidden alignment – A PC with this alignment is viable, but for a very short time. No other of his kind will ever accept to have something in common with him, except maybe slaying him…