I believe he's almost the Shaman King (just one more step!). Yoh and the others need to stop him before he truly becomes the SK. They want to save him because that's the only way to stop him. Otherwise, he can just reincarnate again and cause havoc 500 years later. I have no idea if Horo Horo is stronger than Yoh. Probably not. Yoh's so strong. XD;;

You should still give La Corad a try. XD; Hihara and Yunoki (the trumpet player and the flute player) are such good friends to each other. And Tsukimori and Tsuchiura...they have a pretty heated rivalry.