GameCube

FOREST TEMPLE PHASE

This boss is reminiscent of the battle with Diababa. It works very similar to
that in the weapon you'll be using the Gale Boomerang. Equip that and lock-on
to Zant. All you need to do is throwing the Boomerang at him and he'll stop
floating around and be open for an attack.

He does have an attack he'll use, which is throwing these balls of energy at
you, but it's very easy to avoid and it's blockable by your shield. Keep in
mind that he'll use this attack throughout the duration of these battles.

GORON MINES PHASE

This phase puts you right back in the room where you tackled the giant Goron
that you threw off the platform and into the burning lava. Zant's gimmick this
time around will be to warp around the room and make the platform move all
around. Although it's recommended to use the Iron Boots if you're having
trouble balancing yourself, it's not all that necessary. Watch out for his
energy attack by blocking it with your shield. He'll soon wear himself out and
be open for a fury of sword slices. Attack him a few times here and it'll be
time to switch the battleground again.

LAKEBED TEMPLE PHASE

This phase puts you in the watery deeps of Lakebed Temple. You're going to need
to equip your Zora Armor to breath and also your Double Clawshot and Iron Boots
There will be many different Snake Helmets all around the bottom. They'll be
closed off until one of them opens up to show Zant inside. When he is exposed,
he'll launch an energy attack at you and then wait a few seconds before
disappearing. Use your Clawshot to pull him out of the Snake Helmet and deliver
some blows with your sword. He'll run back into the helmet and the process will
repeat. Continue doing this until Zant switches the scene once more.

FOREST TEMPLE -- MONKEY BUSINESS PHASE

Remember the mini-boss in the Forest Temple? Yeah -- that's this. Zant will
work very similar to the way the monkey did, jumping from pole to pole and then
stopping to throw an energy attack you. Work your away around the energy attack
and wait for him to stop jumping. Roll into the pole he is standing on twice,
not once, to knock him off. Once he's fallen, beat him down with your sword.
He'll jump back onto the poles. Repeat the process a couple more times and
it'll be time for another scene change.

SNOWPEAK RUINS PHASE

This phase takes you right back to where you fought Blizzetta. That means
you'll need to use your Ball and Chain. Each time you hit him, Zant will get
smaller and smaller until he's basically like an ant. When he's in his smallest
state, hit him with either the Ball and Chain again or your sword to reset his
size. Keep this up until he changes the scene for the final time.

DUEL WITH ZANT

In this final phase, you'll fight Zant right in front of the trapped Hyrule
Castle. This is pretty much a one-on-one duel with the man himself; no real
gimmick to talk about here.

He has a few attacks that he'll use in this final confrontation -- one is the
standard slices from his two blades on his arms and the other is a vicious spin
attack. The latter is hard to avoid because it can break your guard fairly
easily. Jump out of the way and use your shield to block both of them though.

After the spin attack, Zant will often be left very dizzy and that's the
invitation to rock him hard with your sword. He'll have other openings when
he's running toward you and just stupidly trying to swing his blades as well.
Once you've hit him enough times, he'll fall to the ground and you'll be warped
back to the Palace of Twilight. Zant defeated.

You should really be asking on the Twilight Princess Q&As, but I don't really care. Happy to help.