A large underground maze under the area that you start in, however with multiple paths to take and dead ends. Also, as you keep taking the right path deeper under the starting area the cave gets as dark as the Tomb and you'll have to deal with quite a few skeletons before you get to the end where you would face a boss which is like a mixture between the flamelurker and the skeledog.
The boss itself would probably be around the same size as Sif but will be very aggressive towards the player. Oh, and like the Flamelurker the boss would get more aggressive as it's health is lowered.
AttacksThe charge attack of the gaping dragon, however it would be able to curve a bit while charging
Grab attack
An attack where it stands on it's hind legs for a period of 7 seconds before attempting to pounce at the player
AoE attack about as large as the Four Kings when it hits half -health
Claw attack
Bite attack
An attack where it stands on it's hind legs, like the other attack, but starts to use pyromancy before performing an attack similar to Manus's dark orb attack (the one that has the orbs surround the area before they come in at you). However this attack would have less coming at you, maybe 6-8 regular sized fireballs.
Defenses78% Resistance to fire
16 % Resistance to Magic
38 % Resistance to Lightning
It would maintain a relatively low poise, throughout the fight however it will slightly increase along with aggression throughout the fight
Poison, toxin, and bleed would be ineffective against it.
Strength weapons would also have a small advantage over other weapons aside from magic.
DropsThe boss will drop one of three things, throughout each playthrough
-Marrow Ring: A ring that could boost health generation.
-Blast Ring: Boosts pyromancy damage.
-Charred Ring: A ring that could boost stamina generation.
The boss itself would drop roughly 30,000 souls upon defeat (or whatever the new currency is) but it would not drop a boss soul.
Boss AreaThe area would start out with the player dropping down into the boss room and into a pool of water. However the area itself is made up of black sand, small pools of lava, and small pools of water with large rock archs being scattered along the sides of the boss room.
The lava itself will do half as much damage as the lava regularly found throughout the rest of the game however, so you won't be punished as much for getting knocked into one of the pools.
The room itself would be the same size as Sif's boss area, so you have some space to move around.
There would be only four major rock formations that you could use to actually keep the boss at bay but for as much time as Gwyn would be kept away from us.
Regular Enemies
I would say that as you start throughout the start of the area you would mostly encounter skeletons that you could beat roughly at the SL 28-35 range assuming your skill in the game. However as you progress the enemies become more demon-like in appearance, something like a mixture of skeletons and the Taurus and the Stray demon but on a smaller scale.
Non-Respawning Enemies
Whatever, enemy that is the replacement of the Dark Knight from the original will be located down here however there will only be one of these enemies.
The other non-respawning enemy will be an aggressive NPC player that will use fire upgraded weapons with an armor set with similarities to Lautrec's armor set and the Channeler set. The player could find the armor in the second dead-end to the right at the end of the maze. (The NPC would be located shortly after running into the demon-like skeletons)
Area
The area itself would be fairly similar to the Tomb yet it would be much more cramped offering not as much space for fighting in the area.
Shortcuts
The entrance to the area would be found after hitting an illusionary wall found under the exit to the beginning area of the game.
The exit however would be a bonfire that would appear after the defeat of the boss.
Bonfires
There would be two separate bonfires found within the area, one half way down into the maze and of course the other after the defeat of the boss.
Unique Equipment
As mentioned before there would be a new set of armor found close the boss door, however there would be a shield found close to the first bonfire that has high defensive damage towards lightning attacks.
Oh and one other thing, I want an illusionary wall at the end of the game that leads to a large statue of GiantDad.