Hi Pharan could you take a quick look at this post please? Multiply Blending not exporting as it should
Subject: Multiply Blending not exporting as it should

Pharan wrote

Ah!
It's actually exported. But the Spine-Unity runtime doesn't support automatically applying multiply blend mode via slot properties.
Like most of the other runtimes, Spine-Unity applies the Additive mode "for free" by exploiting a property of Premultiply alpha blending, and pushing the needed data to vertex colors.

The same can't be done for Multiply.
So it needs to be done by creating a separate material for your multiply parts, then using code like this:

using UnityEngine;

namespace Spine.Unity.Examples {
   public class ApplyMultiplyMaterial : MonoBehaviour {
      

  public Material multiplyVersionOfMaterial;

  void Start () {
     if (multiplyVersionOfMaterial == null) return;

     var skeletonRenderer = GetComponent<SkeletonRenderer>();
     if (skeletonRenderer == null) return;

     var slotMaterials = skeletonRenderer.CustomSlotMaterials;
     foreach (var s in skeletonRenderer.Skeleton.Slots)
        if (s.Data.BlendMode == BlendMode.multiply)
           slotMaterials[s] = multiplyVersionOfMaterial;
  }
   }
}

You can use this shader for your Material if you are using the default premultiply alpha settings: https://gist.github.com/pharan/d24ed2109018c6139d1b883bbf793c66

If you are using straight alpha, you can use any straight alpha multiply shader. Like the Particle/Multiply.

If you really just needed to apply the multiply blend mode to the whole thing instead of per slot, you can just replace the shader on your skeleton's main materials. No extra script needed.