It then came to the drow sorcerer's turn. In an email a few days ago the player had told me that
he had a plan to seal off the Abyssal rift created by the tearing of the Demonwebs and the killing of Lolth [only Lolth's webs had been keeping ultimate chaos of the Abys at bay], that relied upon the second law of thermodynamics. Now was the time for him to explain it. It took quite a while at the table (20 minutes? Maybe more? There was a lot of interjection and discussion). Here is the summary version:
* The second law of thermodynamics tells us that time and entropy are correlated: increases in entropy from moment to moment are indicative of the arrow of time;
* Hence, when entropy reaches its maximum state - and so cannot increase - time has stopped;
* Hence, if an effect that would normally last until the end of the encounter could be turned into an effect of ultimate chaos (entropy), time would stop in respect of the effect and it would not come to an end.
So far, so good, but how is this helping to seal off the Abyss?
* Earlier in the encounter the sorcerer had created a Cloak of Winter Storm which, using an elemental swapping item, was actually a zone of thunder (larger than normal because created while a Huge primordial [as per his Epic Destiny of Emergent Primordial]) that caused shift 1 sq which, through various feat combos, was actually teleportation;
* If this could be extended in size, and converted into a zone of ultimate entropy instead of just a zone of thunder, then it would not come to an end (for the reasons given above);
* Furthermore, anyone who approached it would slow down (as time came to a stop with the increase in entropy) and, if they hit it, be teleported back 1 square;
* As to how a zone of elemental thunder might be converted into a zone of ultimate entropy, that's what a chaos sorcerer is for - especially as, at that time,
the Slaad lord of Entropy, Ygorl, was trapped inside the Crystal of Ebon Flame and so control over entropy was arguably unclaimed by any other entity and hence available to be claimed by the sorcerer PC.
But couldn't someone who wanted to pass through this entropic barrier just teleport from one side to the other?
* On his turn, the sorcerer therefore spent his move action to stand from prone (I can't now remember why he had started the session prone), and used his minor action to activate his Cloud of Darkness - through which only he can see;
* He then readied his standard action to help the invoker/wizard perform the mighty feat of Arcana that would merge the darkness and the zone into a visually and physically impenetrable entropic field, through which nothing could pass unless able to teleport without needing line of sight.
Unfortunately, the invoker/wizard wasn't ready to help with this plan,
and had doubts about its chaotic aspect. On his turn, he instead rescued the paladin and fighter PCs who had become trapped in the Abyssal rift (by casting Tide of the First Storm to wash them back up onto the top of the PCs' Thundercloud Tower).
He also used his Erathis's Beacon blessing - a heal effect - to instead cast Remove Affliction as a minor action rather than the normal 1 hour ritual, which rescued the dwarf PC from Far Realm-induced protoplasmic helplessness. (As is the convention in the game, this non-standard use permanently exhausted the blessing.) The healing unfortunately reduced the dwarf fighter to unconsciousness, but his Ring of Pelor (I can't remember now what it's name is in the rulebook) activated and he turned into a cloud of ash, ready to recorporate next round with half his hit points back, and to take on Pazuzu if necessary.
The paladin then used his turn to bodily pick up the drow and carry him into the control circle of the Tower (at the drow's request).
Pazuzu's turn came around, but he did not re-emerge from the rift. This caused some speculation, but there was a general consensus that he could probably survive the harsh Abyssal forces and so mightn't suffer in the same way the PCs had upon being sucked in.
The drow's turn then came around. He used his move action to fly the Tower up and out of the two zones (darkness and thunder).
He then used a minor action to cast Stretch Spell - as written, a range-boosting effect but it seemed fitting, in spirit, to try to extend and compress zones to create a barrier of ultimate, impenetrable entropy. And then he got ready to make his Arcana check as a standard action.
Now INT is pretty much a dump stat for everyone in the party but the invoker/wizard. In the case of the sorcerer it is 12 - so with training and level, he has an Arcana bonus of +20. So when I stated that the DC was 41, it looked a bit challenging. (It was always going to be a Hard check - if any confirmation was needed, the Rules Compendium suggests that manipulating the energies of a magical phenomenon is a Hard Arcana improvisation.)
So he started looking around for bonuses.
As a chaos mage, he asked whether he could burn healing surges for a bonus on the roll - giving of his very essence. I thought that sounded reasonable, and so allowed 4 surges for +8. Unfortunately he had only 2 surges left, so the other half of the bonus had to come from taking damage equal to his bloodied value - which was OK, as he was currently unbloodied.
He scraped another +2 from somewhere (I can't remember now), brining the roll needed down to 11. The dice was rolled - and came up 18! So he succeeded in converting his zones of darkness and thunder into a compressed, extended, physically and visually impenetrable entropic barrier, in which time doesn't pass (and hence the effects don't end), sealing off the Abyss at its 66th layer.
The unfortunate side effect, as was clarified between me (as GM) and the player before the action was declared, was that - as the effects never end - so he can never recharge his Cloak of Darkness encounter power or his Cloak of the Winter Storm daily.
A modest price to pay for cementing the defeat of Lolth and sealing off the bottom of the Abyss from the rest of creation.