User blog comment:Starchythepotato/Future Units - Old Units' New Forms/@comment-26350740-20150513223402/@comment-25148607-20150513234634

You have to complete book 2 (that is, the current version hasn't released it yet, but the Japanese version has) to get the 4* starters and 5* Hero.

You get 5* Hero by completing book 2, chapter 1, story 1 (by previous experience I'm pretty sure it's in the Vice Capital, is lv45ish difficulty and has 3 stages. but that's just me ranting on lol), and Kain, Michidia, Marina (not really sure about the order of the last 2) from the next 3 stories. So yeah, you need to wait for v2 to get them. Or download the Japanese version.