This would be the next big update to the game! You would have to purchase the mixing station, where you mix the troops. So if you mixed one giant and an archer, you would get a giant that shoots arrows. If you mixed multiple of that troop, but you would need to make the same amount of both. The troop would be the higher lv of the 2 troops. You can't mix dark troops with regular troops. The housing space would be the larger of the two troops.