SPOILER Eldritch Outlook seal n lore n stuff

At the end of A Journey Further, we have to "sacrifice a powerful soul," in order to open the entrance to the Eldritch Outlook. I looked through the wiki but couldn't find any explanation as to how or why it was sealed in a way that requires us to sacrifice Aledar.
I thought that perhaps Bob could've had something to do with it - he did go to Dern to seal the dern beast from my understanding. However, Bob was almost certainly stronger than we are when we defeat the Eye. I have no doubt he could've killed the Eye in our place, even if he was getting old. And it seems to me that the Eye was put in the EO almost immediately after Bak'al is defeated by Bob, so it was definitely there by the time he made his way to Dern. Bob is still the most likely explanation for it being sealed IMO. If we stretch a little, we can extrapolate Bob's power of being able to seal his letter to Nilrem up to being able to seal the gate (See the side note). But there isn't enough motive for me to think it's logical.

That lead me to thinking perhaps it was Bak'al who sealed the entrance, but I can't think of a potential reason for him to have done that. I don't think we have enough information on him to know if he is capable of such a thing either. The Eye might have done it, but once again I'm not sure why. It basically invites us in whenever we kill a key guardian, so what would be the point of sealing the gate?
So that leaves me wondering, how? How did the entrance get sealed off. Who did it, and why? Did the CT working on that quest just really not like Aledar for some reason? Maybe Fruma will give us some explanation, or Dern after, if it ever comes. Maybe I'm just focusing on something that doesn't actually need to be explained.

Side note: Since the gate requires a powerful soul in order to be unlocked, I think it's logical that it would take a powerful soul to have been sealed off. I would've included this with Bob at the top, but there's plenty of crazy things in Wynn so it's not like it's the only possible way it could've been sealed. I also doubt that Bob would've killed himself to seal the gate without having tried to battle with the Eye first.

Any thoughts?