I picked a 'random guardian unit' choice when levelling up a city just to see what I'd get and I got a champion unit. The name of the unit was 'champion'. She had 1 essence, an attack of 1, defense of 0, 12 hits. She also was not a champion, meaning no equipment, no ability to enter lairs/quest locations. She moved fast, but that was all she had going for her, along with a retaliate ability meaning she had a whooping 2 attack when striking back at opponents.

If the game gives you a champion when levelling up a city, it should retain the champion trait and maybe even start with some equipment.

A unit called champion that doesn't act as one is very disturbing.