Do you wish for real online co op?

Astaroth and others, that's all true, but the game -does- have local co-op play confirmed, which I think is what the topic creator is referencing: he wants whatever that is to be online-enabled as well.

There are separate "online challenge modes" as well as the asynchronous features, but it seems that the local co-op stretch goal early on was a separate thing from those modes. If the game is balanced with local co-op in mind, it shouldn't be much different when a friend is grabbed to play it somewhere across the world.

That said, I think the main reason this wasn't included might just be the game data, networking and stability concerns involved. Issues such as:

• As this is the main game we're talking about, whose save data is used?

• If data from both players, whose castle is explored? What incentive is there for player 2 if only player 1 can collect gear/shards and progress through the game? (seeing as only one save slot is being used/updated)
  
• In the event of a game de-syncing, what happens? Is unsaved progress lost, one player carries on, or do both players drop out? If there are difficulty adjustments made to co-op mode, are those adjusted automatically on drop out? (probably not)

It sounds to me like something that could be a lot more trouble than it'd be worth for both the developers and the players. If both players are "Miriams" or equivalent, there's a lot of data/balance/progress concerns to iron out, and if it's just "play as a familiar", it would be largely unrewarding to the joining player, only a very small percentage of close friends type players would be up for that, the same type that would likely love experiencing the already accounted for/budgeted out local co-op together.