system
Given the following post, respond as if you're commenting on Reddit:
human
[Kingdom Hearts] So why could Roxas feel?

I thought nobodies were supposed to not be able to feel, but it was *really* obvious he (along with Axel, I assume because of long term exposure to Roxas) were able to feel emotions.      
    
I know Sora was unusully stronger in the heart than the normal victims, and Roxas wasn't created conventionally, but neither was Xemnas, and he had the emotional range of a Cactus.
gpt
In 358/2 days, Roxas could feel because Sora was never really gone, and he was leeching off of Sora's feelings and memories - his heart. This is part of why Roxas *had* to go for Sora to come back.

In 3D we learn that Nobodies only lack a heart for a short time after creation. Their interactions with others produces a heart, Xemnas had just been corrupting Organization XIII's budding hearts so that everyone would be a huge shitlord.

So a combination of leeching off of Sora's heart, and developing his own through interactions with Axel and Kairi-sue.