Or make a half-succubus template.
Let's see:
fly 40 ft
+4 natural armour
claw damage as per half-fiend but no bite
+8 Cha
kiss = enervation spell 1/day
spell-like abilities by character level or hit dice (whichever you think appropriate):
1st: detect good 3/day
3rd: alter self 3/day, detect thoughts 3/day
5th: suggestion 3/day, tongues 3/day
7th: charm monster 3/day
9th: ethereal jaunt 3/day
11th: greater teleport 3/day
damage reduction: 5/cold iron or good
resistances: electricity 10, fire 5, cold 5, acid 5
immunities: poison
+4 racial bonus to listen and spot
sr = hd +10
If a half-fiend has a +4 LA, this is probably only a +3 LA. If you split it into 3 levels a la Savage Species, you might have something like:
ECL1: 1 HD (outsider d*), +8 Cha, detect good 3/day, one feat, skill points ((8 + Int bonus)*4) with skills being: bluff, concentration, diplomacy, disguise, escape artist, hide, intimidate, knowledge, listen, move silently, search, spot, survival, use rope
ECL2: +4 natural armour, fly 40 ft
ECL 3: claws, enervating kiss 1/day, alter self 3/day and detect thoughts 3/day
ECL 4: (character class) 1st level (now 2 HD)
Cheers
D