Wait I forgot who was hwi?

A member of the squad yang jagak was in.

was he the one who turned into zombie or somebody different? also why was he there as purple spirit is it because his soul is connected to him so he can't stay afar?

Yes, hwi was the one who yang jagak (in ma chunso' body before the loop) made into a surpeme demon jiangshi. Hwi is tied to the soul of yang jagak/ma chunso, and inherited power from the supreme demon arts, and therefore followed him as the loop continued
/started.