Technical Help for a big Fight

[RBVakarian]

So in my current Campaign, the Fey and Dwarves have been at war for nearly a millennia. The campaign was set so players could choose whether to help the Dwarven side or the Fey side. Well, all the players went pro Fey fast and have destroyed the Dwarves super-weapon. My goal is to have the Dwarves come try to siege the city, but the Fey are ready for them. This will lead to full on massive scale combat, (which I need help with coming up with an easy fool-proof set of rules for the team). The battle will culminate in the Fey King and Dwarven Wizard King having an all out magical duel over the battle. The goal is to set up Act 3 of the campaign where the magical back lash weakens the planes boundaries to where portals from he'll begin opening up. I want the backlash to affect the players, but I'm not sure how. I'm also not for sure what to do with the dueling kings after hell portals open up so any help would be appreciated.

TL;DR:
1. I need an easy dummy-proof set of mass combat rules for Pathfinder
2. I need conditions to slap on players based on magical backlash
3. I need a place to stuff God-Like Kings after hell on earth.

[Grod_The_Giant]

For 1, I've always found these (http://paizo.com/forums/dmtyz664?Military-Unit-by-template) to be a good start, effectively removing the "too many NPCs on the battlemap" issue.

[Keltest]

Lets see. For starters, what to do with the kings is easy. Stick them on the other side of the portals. Have a great big rift open right on top of them and suck them through. They can reappear later (or not) having had a harrowing experience that taught them the value of teamwork (or the value of hating each other a lot) as needed.

As for the status effects, what sort of planes are you thinking of making a rift to?

[RBVakarian]

Well, the war has been going for 732 years and he'll has been watching and waiting. So at the very least, the Abyss would pop up; probably the Elemental Planes as well.

[Keltest]

Well, the war has been going for 732 years and he'll has been watching and waiting. So at the very least, the Abyss would pop up; probably the Elemental Planes as well.

Hrm. How about long-term resistances and weaknesses to various elements based on what plane they get affected by? So vulnerability to fire and resistance to ice.

For the abyss, they constantly detect as evil to magical spells and effects, as well as their normal alignment. Perhaps give them a sensitivity to extraplanar residents, but also make them stand out to such as well.

Or you could affect them with raw magic, making them "bleed" random effects at times and otherwise interfering with normal spellcasting unless steps are taken to control the bleed.

[RBVakarian]

That's good stuff. For reference the players are:
Tiefling Wizard -not super optimized
Human Wind Oracle- optimized
Half-Dragon Alchemist- player is afraid of character death without reason
Tengu Rogue
Samsaran Oracle
Dwarf Inquisitor- turned on his people
Elf Slayer- new to game

I like the idea of switching things around to keep them on their toes. It's real hard to stay ahead of them. They accelerated the Act 2 of the campaign seeing an impossible threat (ancient dragon working with the dwarves) and taking it down. Elemental shifts could be fun.

[Keltest]

You could also do things like unleashing invisible stalkers on them, giving them the feeling that theyre being watched without actually having any in game effect at all, other than to make them confused and paranoid.