This story belongs mainly on the Heartwarming page, but what brings it here is the events in chapter 37 (which basically confirmed that Muneca was the little girl)... more specifically, Daryl discovering that Muneca is covered with burn scars. Think about this: Muneca was only a little girl when she got caught in that fire, and apparently, she was burned up pretty bad...
Yuma’s story. He was a simple Buddhist monk who merely wanted to be left alone. Unfortunately, due to the blundering of two European Pacificators (one knocked a lit candle upon Yuma’s lap), they awoke a “great rage” within Yuma.
Bismun: And you killed those two Pacificators?
Yuma: Regretfully, yes. With that, I’m no longer a Buddhist, and my rage have cast myself to Naraku.
In the end, Yuma was just an old man who found himself trapped in a situation beyond his control for a very long time, and just wanted to go back home.