So I was doing a re-watch of the FDTD Season 3 Finale (of course), and noticed something interesting.
When Richie was in Xibalba, Carlos made the suggestion that he was meant to cross to the other side because he was part Xibalban, and he could get out of hell. He says: “When the sun comes out from behind that moon, you got one job and one job only, and that is to save tu hermanito (your brother), or it all goes down the drain.”
When we see Kisa wake up, the sun is beginning to come out from behind the moon. And not long after that, Richie walks out from Xibalba, leading Kate the way out of hell. If Richie hadn’t been there, he couldn’t have used his special powers, the ones Carlos hinted at, to get Kate out. Because getting Kate out meant saving his brother. Because Seth couldn’t make it without Kate.