Played some with Joseph and noticed a lot of skill descriptions to be misinforming (description says it gives X bonus, but the ability actually gives Y bonus), I wrote some down but some I did not. For cases like Necromancer's Ghoul or most ultimate abilities it's okay to leave out the details in the selection screen, but I do not think it is okay to misinform.
Warrior Mage - "Disarm", I'll provide images for this one just to better explain what I'm talking about:
https://imgur.com/a/cGnZn3Y - ability selection screen and actual ability
Footman ultimate form Heavy Armor - actual ability reduces damage taken by 200, but in the Hero Abilities screen it gives different numbers
Monk - Meditate very small difference - selection screen description says Level 9 heals for 3200 but hero ability on level 9 says 3000
Black Mage - "Thunder" selection screen says 3800 damage, actual ability says 6000 damage.
There were some inconsistencies in non-ultimate forms, but I didn't write those down.
While I'm at this, fun fact: You will regress a total of a whooping 41 levels in order to reach the Ancient Vampire form, which is the most expensive out of all Little Child forms (alongside Vampire Lord of course). Azaran Locksley wink wink.
Added (2020-05-06, 10:37 AM)
Regarding my previous post, I forgot to mention something.
Monk: ultimate ability final level - description says it gives 4000 armour bonus, but it actually gives 2000. Or something like that, I know there was a big difference.