hong said:
Note also that the dragon will in all likelihood have mage armour, shield, cat's grace and haste going, for an AC in the 40s or even 50s. It's unlikely you'll hit with everything.
True enough... but all said rogue needs is "one good shot."
Let's look at the numbers again... regardless of Dragon's AC, let's assume for sake of argument that said twink will have high enough attack bonus to autohit creeping doom bugs....
Step three: Twink unleashes a Whirlwind Attack. Gets one shot at Dragon at highest BAB as part of WA. Also gets 187 shots on the swarm (1000 1-hp creatures in a 16-square area of which the twink gets a shot at 3 squares). On average, the twink connects on 178 of these shots (hitting on everything but a natural one), leading to 178 Great Cleave free attacks on Dragon.
Thus, sequence goes:
WA Attack on Dragon - WA Attack on Bug #1 - GC Attack on Dragon - WA Attack on Bug #2 - GC Attack on Dragon - WA Attack on Bug #3 - and so on.
Net result...
179 Attacks (1 from WA plus 178 from GC) on Dragon
Remember that a 20 is an autohit (hope your DM hasn't nerfed that rule). That means, on average, you'll see 8-9 hits REGARDLESS of how gawdlike the Dragon's AC is. Call it 8.
8 hits is not too bad. Not great, certainly, but not bad... dump everything into getting a high Str (26 is possible for a +8 attack bonus and thus a +12 Str bonus on hits; you don't need to twink Dex for this variation)... you get an average of:
8d8 (sword) which is 36
8d6 (flames) which is 28
40d6 (sneak) which is 140
96 (str)
32 (+4 weapon)
or an average of 332 hp plus 8 Str damage. Not ungodly, but still not too bad. Remember, this is assuming you only hit on a natural 20.
If you get the nastier version (overlap 3 Creeping Doom Spells so that 7 of the 8 squares surrounding the character have Doom in them) you get 415 attacks due to downed Doom Beetles... on an "only natural 20 hits" kick you get on average (rounding down) 20 hits and 2 of those are crits (in effect, 22 hits). That ups your minimum damage potential to
22d8 (sword) which is 99
20d6 (flames don't double with crit) which is 70
88d6 (sneak) which is 308
264 (str)
88 (+4 weapon)
or 829 points of damage plus 20 points of Str damage. Again, nowhere near as lethal as the earlier proposition, but when you consider that this can be treated as the LOW end of damage you are GUARANTEED to deal, I think it's a darn fine alternative.
--The Sigil