Just revisited Springtrap's dark story—still the most tragic character in FNAF?

I recently explored Springtrap's story again for a deep dive video I made (I wont link it, but its posted over on YouTube if anyone's interested), and honestly, it reminded me just how haunting and tragic William Afton's transformation really is. Springtrap's story feels uniquely dark, especially compared to other animatronics.

What do you think makes Springtrap's story resonate so strongly? Is it William's backstory, his twisted fate, or something else entirely? Curious to hear your thoughts!