[Tancred]

Personally speaking, I've never liked fighting Dragons hand-to-hand. My advice? Get as many party members to open fire with missile weapons as possible on Draconis. This goes for his human form too - that way, you'll avoid the worst of the effects of his immediate wingbuffet when he becomes a Dragon. Use one tough character as a 'lure' - probably the one with the least missile firing capability, like Korgan. Give him Boots of Speed (oh, god, give him Boots of Speed!) and PLENTY of helaing potions. He'll act as a runner, keeping Drac busy while you pelt him with spells and bolts. If the lure is wing-buffeted and Drac targets another party member, fall back - have your party scatter, and have that character act as a new lure until the original lure gets himself ready to run again. You'll have plenty of room to run. There is no excuse NOT to have Hasted the party.

Personally, I cast every single defensive or enhancing spell I could before fighting Drac, and it was STILL hard.

If you don't have any missile capability, I'm amazed you got this far.

Good spells - Keldorn, Viconia, yourself and Jan are all capable of cating True Sight. Use it. Use Spell Sequencers - I find a triple-whammy Spell Trigger of Breach, Pierce Magic and Lower Resistance/Remove Magic works excellently, but have multiple memorisations of Breach, Pierce Magic, Dispel Magic and, if you can get it, Spellstrike - or, more offensively, if it looks like Drac is about to fire off some unpleasant spells, I use three Magic Missiles simultaneously. ONE of those damn missiles should get through, distracting his spellcasting. Note - use of Dispel Magic will cancel spells like Haste, but sometimes you need it (to counteract a stun on one of your party members, for example). Keldorn should be able to deal with your dispelling needs, but make sure you have some backups in case he dies or gets stunned. Area-of-effect spells that don't affect the party like Comet and Abi-Dhalzim's Horrid Wilting are excellent. As menioned, Mordenkainen's Sword is fantastic, far better than even a Planetar or Solar. Summoned creatures that can be killed will die, swiftly.

Keep a Rod of Resurrection handy. You'll need it. Make sure everyone has enough healing potions - time spent dishing out healing spells is time not spent hurting Drac. If one party member is too badly hurt to continue, don't be afraid to run. Pause the game often to keep track of the action. Make sure you've got emergency supplies; Oils of Speed and Potions of Invisibility for all as backup, useful scrolls handy, any neat magic items standing by in quickslots, etc.

Stuff that lowers spellcasting time is fab! The Robe of Vecna is excellent for making SURE those spells go off quickly, as is Lower Alacrity; but generally Lower Alacrity is best used in conjunction with Time Stop, because once you cast 'Lower' you commit yourself to casting spells, and if you have to run for your life at that moment, it's a bit of a waste...

Don't expect to win first time. Don't get annoyed. Be prepared to fight on in the face of deaths - there's always a chance you'll win out. Gradually, you'll get used to the battle of attrition and resource management that you have to fight here.