The final boss, as you know, is the champion of Chaos who seeks nothing but to return Hyrule to formlessness. I've been calling it "Lord Menace" (which is short for my original name, "The Shadow Phantom War Lord Menace from the Dark Nation") but the in-game characters probably won't refer to it by name very much.
It is composed of elemental Chaos, and as such its only weakness is elemental Order - manifested in the Triforce. However, Menace is concentrated enough to overwhelm the Triforce's powers, as long as each piece is separate and fragmented. There is one fragment each of Courage, Wisdom and Power imbued in the Golden Arrow, Ring and Sword, respectively, which prevent the Triforce from re-forming when you gather all three pieces.
* Goddess Temple interior (Chaos World analogue of the Forest Temple)
Several block combos of various sorts are present.
* Golden Arrow
* Magic Quiver
* Hover Boots L2 (Endless)
* If Link did not kill Zelda, then he is still carrying her prone form on his back. This reduces his walking speed slightly.
Menace's first form resembles the outline of a powerful biped, composed of "rainbow static", similar to the NES Bubbles. For your convenience, it drifts around in lieu of walking.
One of Menace's defining attributes is that it has the terrible power to revert any matter it touches into primal Chaos. Thus, all of Link's weapons (except for the Golden Arrow, which he must have at this point) are not only useless, but susceptible to destruction.
If you throw the boomerang at Menace, the boomerang will change into a Chaos Keese and be removed from your inventory. If you slash Menace, your sword will turn into a Chaos Gel and be removed from your inventory. (Since you receive the Golden Sword after the First Form, this doesn't matter.) The only weapon that damages Menace is the Golden Arrow (and since you're also forced to have the Magic Quiver at this point, you can't run out.)
This brings me to another point: every mêlée attack that Menace's First Form uses is, barring the use of Nayru's Love, a one-hit-kill. Zelda will mention this if she is still alive.
That said, here are some ideas for attacks:
* Menace slowly drifts around the room toward Link. Any block combos it passes over change to floor combos, and Chaos Zols are created.
* Menace shoots a spell rocket up, and rubble falls from the ceiling all around. Those that land on Menace transform into Chaos Keese.
* Menace grows an "arm" (see Death Eye in LA) and swings it around. Any block combos that the arm touches change to floor combos, and Chaos Zols are created.
After taking sufficient (12) damage, Menace's sprite changes such that it is now touching the floor. The first attack is replaced with:
* Menace slowly drifts around the room toward Link. Any block or floor combos it passes over change to bottomless pit combos, and Chaos Keese are created. (Since Link has the L2 Hover Boots, this doesn't matter.)
Menace's form dissolves into a dozen individual "Chaos clouds" (1x1 circles of transparent static). These are gaseous, such that the Golden Arrow can't damage them. Most of the arena should consist of bottomless pit combos by now, on which shall be drawn an animated starfield.
If Link killed Zelda, then her ghost will appear now and tell him that he must abandon the Triforce and escape.
Otherwise, Dim's ghost will appear, and after consoling Zelda, will give Link the Golden Sword and Golden Ring. He can then take on the Second Form.
* Golden Sword
* Golden Ring
* Hover Boots L2 (Endless)
Menace consists of 12 Chaos clouds. These orbit at various angles around a central point.
Here are some attacks:
* Each cloud fires a Fireball 2 (which, with the Golden Ring, hit for one heart) in rapid succession.
* Patra-style: The clouds start spinning in a circle around the central point, extending into a ring. This ring drifts toward Link.
* Vitreous-style: A few of the clouds rush at Link, before returning to their orbiting position.
* Fire Bar style: The clouds form a line, which spins around while drifting toward Link.
* Counterattack: whenever Link slashes the sword while Menace is in its "normal" state, all of the clouds will fly away from each other, and then converge at a different point elsewhere on screen.
As Link has the Golden Ring, contact only does 2 hearts damage. Each cloud takes 24 slashes (or 12 spin attacks) to destroy.
Once 6 clouds have been defeated, the remaining clouds will move into the center and fuse into a single Orb. Zelda tells Link to hold up the Triforce. The Golden Arrow, Sword and Ring reunite with their respective Triforces, and the complete Triforce will be unsealed. A golden light shines forth onto what remains of Lord Menace, erasing it.