Greenfield
Adventurer
I will observe that, as a Sorcerer, you can use 4th level spell slots to fire lower level spells. And you should definitely consider See Invisible for yourself, so you don't shoot your allies. And, of course, they'll be at risk for running into/shooting each other.
Also remember that Greater Invisibility only lasts 1 round per caster level. If you're 11th level and are casting 7 of them prior to the combat, then the first one you cast only has 4 rounds of cover, max, before it goes away.
So consider this: Wall of Force set to clog the cavern entry, but not fill it perfectly. Have the bottom a foot off the floor, or the side a foot away from a wall, so you can cast spells over/under/around it. Since you can't have the WoF intersect with a solid object anyway, there's going to be a gap somewhere. Make sure it's where you want it, and can take advantage of it.
Now, while he's worrying about the Cloud Kill you dropped in there, you're dropping fireballs and lightning bolts as fast as you can, shooting under the wall, again and again. Use 4th level slots for these, to increase the total number. Save a Black Tentacles though. At some point during the fireworks, he'll try to assume Human form (one of a Dragon's powers) to slip past that barrier. As soon as he tries, tentacle him. He loses Draconic strength and size mods in Human form. But wait until he's near the cave wall, trying to slip past your barrier, when you drop it. And then drop a second WoF to pin him against that wall so he won't be able to change back to a dragon. He'll literally be caught between a rock and a hard place.
Also assume that your plan, being elaborate and detailed, will fall to pieces on about round 2. So make sure you have a "Plan B", and probably a "Plan C" prepared as well.
Have fun!
Also remember that Greater Invisibility only lasts 1 round per caster level. If you're 11th level and are casting 7 of them prior to the combat, then the first one you cast only has 4 rounds of cover, max, before it goes away.
So consider this: Wall of Force set to clog the cavern entry, but not fill it perfectly. Have the bottom a foot off the floor, or the side a foot away from a wall, so you can cast spells over/under/around it. Since you can't have the WoF intersect with a solid object anyway, there's going to be a gap somewhere. Make sure it's where you want it, and can take advantage of it.
Now, while he's worrying about the Cloud Kill you dropped in there, you're dropping fireballs and lightning bolts as fast as you can, shooting under the wall, again and again. Use 4th level slots for these, to increase the total number. Save a Black Tentacles though. At some point during the fireworks, he'll try to assume Human form (one of a Dragon's powers) to slip past that barrier. As soon as he tries, tentacle him. He loses Draconic strength and size mods in Human form. But wait until he's near the cave wall, trying to slip past your barrier, when you drop it. And then drop a second WoF to pin him against that wall so he won't be able to change back to a dragon. He'll literally be caught between a rock and a hard place.
Also assume that your plan, being elaborate and detailed, will fall to pieces on about round 2. So make sure you have a "Plan B", and probably a "Plan C" prepared as well.
Have fun!
