Before I start I want to point out that while the giant mech boss in this game is called Zakat, the word also refers to the act of giving to charity as one of the 5 pillars of Islam. I have no idea of why the giant mech is also named Zakat seeing as Anubis and Jehuty are from Ancient Egyptian mythology, but I could be missing something. If anyone knows why a Japanese gaming company might have decided to name a giant death machine after an act of charity to the poor please leave a comment.
ANYWAYS There are two parts to the boss battle.
Part one: Use dash to dodge his beam attacks while closing in on him. Doesn't hurt to let off a few homing beams while you're at it. When the forcefield is down get behind the outer shell and hit the, shall we call it stalk of the machine,
When the shield is up grab one of the panels (wisp is good here) and use is as a shield against his beams. The shield will deactivate once you have removed a few panels. Sometimes he will charge you in which case Dash to dodge. Once the shields are down again continue attacking it's stalk with your blade. Rinse and repeat a few times.
2nd Part- Even easier. Dodge his attacks, use homing beam on the mine like things, and slash at the face of the machine as soon as the shield goes down. When this black ball thing shows up dodge it and shoot at it until it goes away, Really there ain't much to it.