These fights only take place if you skipped the Divine beasts (like Any%). The Blights are stronger forms of the original dungeon boss fights. Each fight is divided into two phases.
Shoot him in the Face.
Already dead (if not then just hit him a couple of times)
Throw the boomerang into his face until he moves, then dodge his spear and spin between his left arm and body with the stone smasher( try to get double hits on his arm), keep spinning until you run out of stamina, the slam stuns Waterblight for about more 4 hits(jump after every second one) and one jump attack. If you did not get the one cycle, just walk up to where he spawns next and spin attack him until he moves to phase 2.
Switch to boomerang and try to pick up the arrow from shooting Windblight (Its lying on the ground near the left side of the balcony) then headshot Waterbight twice sprint up to him and hit him 6 times with the boomerang. He will teleport and then you have to headshot him twice again and finish him off with a spin attack with the stone smasher. (Note: Make sure to have the Stone smasher equipped)
Immediately pull out the stone smasher and spin, after the third hit let go of Y. Spin again letting go of Y on the third hit, this should stun him, if not try to dodge his attacks and hit him with a flurry rush using the royal guards sword. If you are successful hit him with the royal guards sword until he moves to phase 2.
Plant a square bomb in the middle of the room and wait underneath Fire Blight until the bomb gets sucked in. Blow it up and wack him three times with the royal guards sword then jump and use the royal claymore getting double hits to one cycle him.
In the second phase of the fight, Calamity Ganon surrounds himself with a shield, making him pretty much invincible until the shield is down. Luckily it is possible to permanently stun lock him with a precise timing on the hits. To kill him, reflect one laser to get the shield down, then perfomr the stun lock as seen below. Make sure to let go of Y when his spear touches the ground after he picks it up.