Good day!

Is that possible to check cross-character quest completion status?
If not, is this option in plans?

Thank you for Grail! It is very helpful.

Best regards,
Alexander.

At the moment Grail keeps track on what quests are completed on a per-character basis. So theoretically this might be possible. However, it would require two things: (1) the name/realm of the character against whom to compare, and (2) the ability to load the file that Blizzard uses for per-character saved variables. I have no idea if #2 is possible, and would guess that it is not. In this case, then in the current design it is not possible. However, if #2 is possible, or Grail were redesigned to store the per-character information differently (which I am not thinking it a good idea as the data would get big especially with 50 characters possible) then it could be done with a bit of effort.