He's now available in Kingdoms by default.
Ty Red Hook.

Requires editing a json file but I'll try to make this straightforward.

1. Close the game.
   
2. Find your profile save at C:\Users\(username)\AppData\LocalLow\RedHook\Darkest Dungeon II\SaveFiles\(SteamID)\profiles
   
3. profile_1.json or another number if you have more profiles.
   
4. BACKUP THE FILE SOMEWHERE SO YOU CAN REVERT IF NEEDED
   
5. Search for "m_UnlockContainer"
   
6. Inside that you'll see "m_Unlocks" followed by a list of all your unlocks.
   
7. Add the following to the list at the end
   
   "herostory_ABM_01", "herostory_ABM_02", "herostory_ABM_03", "herostory_ABM_04", "herostory_ABM_05"
8. It'll end up looking something like
   
   "m_UnlockContainer": { "m_Unlocks": [ "very_cool_unlock_1", "very_cool_unlock_2", "herostory_ABM_01", "herostory_ABM_02", "herostory_ABM_03", "herostory_ABM_04", "herostory_ABM_05" ],
9. Start a new confessions run (Dunno if this is needed, but I did it) and exit when you can.
   
10. Start a new Kingdoms run and enjoy.

>Cool new mode that looks like it'd be fun comes out.
>Gets DLC for cool hero I remember from the 1st game.
>Can't use in the mode I actually want to play?
>????????
I don't enjoy confessions and don't want to have to play it to unlock the DLC hero.