Xelthia "Backspikes" marking does not visibly change sprite

[SlappMann]

📋 Description

Explain what the bug is and what you expected to happen instead.

Xelthia "Backspikes" markings do not change character sprite
Xelthia backspikes are visible through clothing (unsure if this is intentional)

---

🔁 Steps to Reproduce

List the steps that consistently cause the issue.

1. Create a Xelthia character
2. Go to Markings > Overlay and add "Backspikes" marking
3. Change the color of the backspikes, and the sprite does not change

---

💥 Expected Behavior

Describe what you expected to happen.

Changing the color of backspike markings should visibly change the sprite

---

🧠 Actual Behavior

Describe what actually happens.

No visible change to sprite

---

📸 Screenshots / Videos

Attach any screenshots, clips, or logs that help show the problem.

---

🧩 Notes

Anything else that might help contributors reproduce or understand the issue.
Add any other context about the problem here.

I would guess that the "Backspikes" marking is being applied with 0 opacity