Yes, Raise Dead will be pretty hard to come by. There are some ways to get it cast, but it's probably going to take us quite a lot of posts... Animate Greater Undead might actually be an option, though I'm not sure Dariel would appreciate that (undeath being a rather uncomfortable according to many sources.)
I agree it's not an automatic victory, and he's going to need a night to prepare the right spells. But with Fly, Displacement, Shield and Stoneskin precast he can move out of the Troll's reach round 1 and can probably survive the Troll's first attack. Then he can easily pump out enough acid to kill the beast, with intelligent use of Hold Monster he can make it very hard for the troll to resist his spells effectively. ( I doubt the Troll is a Half-Green Dragon. If he's half-anything he's probably Half-Fiend (fire and acid resistance 10) or Half-Red Dragon (Fire Immunity) I saw nothing in Endur's description of the Troll about it having wings, so flying will probably be quite safe. If it has ranged weapons a simple Protection from Missiles can easily be cast. Anyway, the group can easily make some innocent inquiries in the bar about the troll to learn the specific strengths and weaknesses (it is the greatest fighter in the arena, it will be very well known. It might even have a fan-club

)
Yyssiriryl may be a bit disgruntled, but the Matron Mother has strong suspicions that she took the Troll for herself out of the shipment of Slave-Trolls meant for Quellar Millithor. (Endur told me about that). Drow pretty much expect each others to stab them in the back, Yyssiriryl will understand, she might even respect us more for our ruthlessness. We did save her life, we might still be counted among her friends.
Also she has her own position to consider... Would she have anything to gain by turning against us? If she seems too upset we could always offer her some compensation. Ki'Willis has a Diplomacy of 20, she'll think of something.
