Plane Sailing
Astral Admin - Mwahahaha!
Arguably a dragon defending it's lair is weaker than one in the open - since it loses it's fantastic mobility which is key to a dragons survival against parties. However, lava pools are particularly good for red dragons...
In this case the dragons best bet is to grapple targets and swim under the lava with them, since the 70 average damage per found from immersion in lava will help take the fight out of them pretty quickly. He can also get full cover (+8AC and improved evasion IIRC) by swimming in the lava with just his head poking out.
So I'd probably assess this situation as especially challenging and give +50% xps if it was overcome successfully.
In this case the dragons best bet is to grapple targets and swim under the lava with them, since the 70 average damage per found from immersion in lava will help take the fight out of them pretty quickly. He can also get full cover (+8AC and improved evasion IIRC) by swimming in the lava with just his head poking out.
So I'd probably assess this situation as especially challenging and give +50% xps if it was overcome successfully.