User blog comment:Teridax122/Human hosts and Human forms/@comment-6532857-20150209060906/@comment-5527544-20161012151503

The original Tiga, who, given the reaction of the Dark Giants, probably had a human form that looked like Daigo. Amui, who was possibly another reincarnation, Daigo, and then Tsubasa.

That's two confirmed human forms, one possible human form, and Tsubasa who temporarily took on his form and some of his powers. Then there is the kid from the X movie, that's five Tigas.

Also, there's the Tiga from the Dyna movie (which is strange since I though Daigo had been unpetrified, so why was the statue still there?) form from the light of mankind.

Which is five and possibly six if we don't count the Dyna movie instance as the same as the original Tiga.