During this Phase Koloktos’ has two main attacks; one will be to smash Link with its elongated arms, while the other is to toss the two blades that are being held in a boomerang type fashion. Simply dodge out of the way of these attacks and when Koloktos’ arms are stuck in the ground, have Link grab the valves using his whip to disable them temporarily. Repeat this process until Koloktos no longer has any arms that are able to protect the red jewel located in its chest. Once you have done this enough times, the boomerang blades will shatter signaling the start of Phase 2.
Koloktos will pull itself out of the ground becoming mobile, each of its six arms will become armed with a scimitar fashioned sword, and a grate will also appear over Koloktos’ weak spot in its chest. Koloktos will now attempt to mow Link down with an alternating sweeping motion from each set of arms. It also now has the ability to summon three Cursed Bokoblins to attack Link in addition to the smash attack that it previously possessed.
This is where patients and staying calm becomes key to defeating this boss; simply wait until Koloktos does its smash attack and use Links whip to disable all three arms that Koloktos attacked with. After doing so, Link can now pick up one of the Sabre Swords that the arms were holding. Once equipped with a Sabre Sword, get close to Koloktos and perform a horizontal slash to its legs as this will cause the boss to fall allowing Link to attack the grate (using the sabre sword) protecting the red jewel and ultimately attacking the jewel.
Repeat this process two more times and enjoy the show as yet another boss goes up in a puff of smoke.