Board Thread:Questions and Answers/@comment-67.176.129.52-20150301071508/@comment-70.65.208.248-20150311112352

Checked out the forums on the main game site. basically in order to get to level 50 for any unit it will require 8 of those units total.

1 starter

2nd for level 10 progression

3 and 4 for level 30 progression

5 6 7 8 for level 50 progression

basically when a unit evolves where you have a option to choose a perk you have to have two units of similar rank to advance it.