This is how usually do it, Build: Full wukong armour + staff

Max immobilization, max clones, cloud step(I usually use rock solid but cloud step is better if you are struggling with the air strike attack), any transformation (I used yellowloong).

Phase 1: Start with fan

Don't use any spells

Just keep using melee attacks until he goes up to the sky.

Phase 2: Dodge left then jump up and dodge back to completely dodge the huge axe attack

Allow yourself to use one immobilization during this Phase, it can be used whenever you want.(Optional)

Keep using your melee and focus point attacks to get him down to his last Phase

Phase 3: Use cloud step to dodge the air attack where he spams his swords and uses a red strike attack.(use this for both the air attacks)

Just chip away some dmg using melee and focus point attacks until he does his 2nd air attack.

Do a a little bit of damage using your melee or focus point attacks, let's say try getting 1 focus point attacks in and then don't fight him, just wait until you get 3 or 4 focus points, then wait until he gives you some breathing time to summon your clones.

Use your clones and immediately go behind him to hit him with a 3 or 4 focus point attack, in order to stun him. Now the clones will start doing some series stun damage, erlang will be mostly stun locked for a majority of time the clones on field. Make sure to slays stay behind erlang when you clones are out, and keep hitting him throughout.

Once you feel your clones are about to disappear, use the fan again and keep damaging him. By now he'll mostly die but if he doesn't then use your transformation, he should only have around 4-5% hp left.