I just want to preface by saying all my suggestions (especially about what constitutes a +2 LA) are just that, suggestions. I'm no expert. Ultimately, as DM, you should make or rule whatever you are comfortable with.
I think what I've outlined below is a +2, albeit a STRONG +2. The crossbow thing actually knocks a lot of wind from the sails. The player knows you have Kryptonite on him whenever you need it. Make sure that he remembers that vulnerability, like vampires and garlic, and it should be great.
Some of what I'm going to discuss will be within an aasimar/tiefling (A/T). I know they are +1 only and not a prime example but I think they'll do.
In the MM, Rakshasas as characters have no bad stats (+2 STR, +4 DEX, +6 CON, +2 INT, +2 WIS and +6 WIS). SS has the starting abilitiy adjustments at +2 CON and +2 CHA. Given that these are its strongest abilities (according to MM), I wouldn't mind allowing just those two bonuses. Maybe add a -2 WIS for a rakshasa's bloated ego and self-assurance.
I was only saying there are allowances at a sliding scale if you wanted to have more than just a +2 CHA. A +2 CHA by itself is fine. Fits right in the scale for A/T.
From SS: Vulnerable to Blessed Crossbow Bolts (Ex): Any hit
scored with a blessed crossbow bolt instantly slays a rakshasa.
this is a unique roleplaying oppurtunity that both myself and the player are aware of and comply to. As a DM i would never give the enemy's blessed bolts unless it was worth the risk. example: someone wronged by the rakshasa learns of this vulnerability and uses it to threaten him into helping him in some way. Then the player can make the decision of whether he will be able to talk his way out, hide behind the party, or comply with his wishes. Either way it will be a challenge where the risk (instant death) is worth the reward (which for his character would be great power or wealth).
This is what I was talking about in disliking the SS. If it is something cool then by all means use it. If anything a niche penalty can offset the LA a bit so its good. Outright kills eh? Nice. If I may, I don't have direct access to SS, does it have to be Crossbow?
I've realized now that the MM Rakshasa and the SS progression are different. Which is why certain abilities like Change shape(MM) and Alter self (SS) are present. SS has spell immunity, MM spell resistance. Anyways...
Whenever possible, I would recommend using the MM version of ANY ability as it will be more standardized and should work out better in 3.5. *shakes fist at SS*
-I guess I will cut spellcasting as he is already using a spellcasting class that he created (Which might be a topic for another thread), and I can see how that could easily unbalance the level adjustment.
-For spell resistance, How low could I go to include this? I do see it as a bit vital to a rakshasa in the way of role playing (They are naturally resistant) . So if a low level spell resistance could be included that would be great. If not, meh.
-Natural armor bonus of +2 or +1 would be fine. At least one since it makes sense (to me at least) that a rakshasa would have the tough fur.
-I didn't want to include a bite just because a 1d6 on hand always seems pretty good in its own right. But if isn't too much I will definetly include it.
-As for skill bonuses, I guess a +2 bonus on bluff and disguise (+4 on bluff when using detect thoughts and +4 on disguise when using change shape). This is close to what the MM lists its skill bonuses are and how they are effected by its natural abilities (Change shape and Detect thoughts)
-Change shape 1/day for 3 hours would be nice but the duration could be lower. and Detect thoughts 1/day would be just as nice (I neglected to mention that this would not be at will). Both of these abilities I see as essential to what a rakshasa is, yet can be discarded if it would be too much on the level adjustment.
- Spellcasting: I'm glad we agree.
- Spell Resistance: I would go with a copy of the monk's diamond soul ability, minus the class requirements. If you think 10 + Level is low, I recommend trying it out and then bump it to 15(or 20) + lvl if need be.
'Diamond Soul (Ex): At 13th level, a monk gains spell resistance
equal to her current monk level + 10. In order to affect the monk
with a spell, a spellcaster must get a result on a caster level check
(1d20 + caster level; see Spell Resistance, page 177) that equals or
exceeds the monk’s spell resistance.'
- Natural Armor: +2 or +1 doesn't make much of a difference. I might cut it entirely but I'd say its your call what number you want.
- Bite: You are right, with the toolbox this player has, no bite.
- Skills: Make Disguise and Bluff class skills but no bonuses from race. Then give the line from the monster's description.
'*When using change shape, a rakshasa gains an additional +10 circumstance bonus on Disguise checks. If reading an opponent's mind, its circumstance bonus on Bluff and Disguise checks increase by a further +4.'
- Change Shape: 1/day is great, no better or worse than A/T's daylight/darkness. I'd have no length of use. Once a day is good enough.
- Detect Thoughts: 1/day too, cool. Use his caster level (you said he has his own casting class right?) as the duration and DCs and otherwise I would base it on the spell.
I understand this might seem like I'm trying to fit it all into a narrow space, but I am completely open to what can be toned down or completely removed as long as it still seems like what a rakshasa would have naturally (Without any development into a full blown one) and still maintains that +2 level cap.
I guess if there was anything that should be first to go I would say spell resistance and then AC bonus. Detect thoughts and and change shape are pretty crucial to character he wants to play (A deceiving, power hungry tyrant).
If there is anything that I was not clear on or could include please respond. I'm really glad you're helping me and I know the player will be even more glad.
Everything seemed clear. I'm glad I knew you thought the change shape and read thoughts to be vital.
What I was trying to get across before was that this Raksasha is a younger or junior member of the species. In time he would have developed into the 14 lvl adjust creature but this is a "baby" form.