Hyrule Warriors' giant bosses shrug off almost everything you throw at them. Each one has a moment when it is open to a particular item. Hit it with that item and it drops, and a Weak Point Gauge appears above it. Attack until the gauge empties and you land a Weak Point Smash, a huge hit that takes a big chunk of its health. Enemy warriors, such as Volga or Ghirahim, work the same way: their gauge appears briefly after some of their attacks.
The giant bosses' attacks hurt their own troops too. In Hyrule Warriors Legends and the Definitive Edition you can also bring several of your warriors to a giant boss at once for a Smash Boost, which refills everyone's Magic Gauge and raises their attack.
It rolls up into a ball, stomps, breathes fire and spits fireballs. Before it breathes fire it inhales deeply. Throw a Bomb into its open mouth while it's breathing in, and it collapses with its Weak Point Gauge showing.
Gohma guards its eye behind its armored forelegs. It swipes, spins, charges, jumps and fires eye lasers. Right after a laser, or while it stops to charge a big blast, its red eye turns blue. Shoot it with an arrow then and Gohma flips over.
Four heads covered in a hard metal hide. It spits seeds at you and at your base, bites, uproots itself to rampage, and leaves pools of poison. Now and then its heads lose their metal hide for a moment. Stun each one with the Boomerang, and once all four are down, the crystal in its bulb opens up.
It stays in the air, charging, whipping up whirlwinds and breathing fire. When the tip of its tail glows blue, during the whirlwinds or its fire breath, Hookshot the tail to drag it to the ground. In The Shadow King it flies too high at first: take Lana or Midna to the keeps it attacks to bind it with Magic Circles, until the Great Fairy finally brings it down.
Just as in Skyward Sword, it stomps around sending out shock waves. Hack away at its eight toes until it falls, then its whole body is open. Past half health its steps give off electric shocks. In Sealed Ambition it flies up to attack your keeps; fire the Groosenators in those keeps to knock it down.
The final boss. Ganon is fought much like the bosses before him: use each of your items at the right moment to break away his armor. With the armor gone, Zelda hands Link the Light Arrows to finish the job.
The giant bird from The Wind Waker, added in Hyrule Warriors Legends along with the Hammer item. Smash its mask with the Hammer. In A New Disturbance you only have to drive it off; in The Search for Cia you break its mask and then finish it.
He spins with his sword, teleports, makes copies of himself and throws energy balls. Hit his single white energy ball back at him to open his Weak Point Gauge. Below half health he draws a second sword and comes down to fight up close, blocking from the front and sides. Get behind him and attack his back until he falls.
The story also pits you against warriors: Cia, Volga, Wizzro, Ghirahim, Zant, Ganondorf and, in some scenarios, your own allies or dark copies of them. They block and dodge like you do. Wait for an attack to finish and look for the Weak Point Gauge over their head, then attack it.