You decide to meet with the emissary in public.
"King Estjald denounces this outrageous attempt at chaos, Emperor!" The diplomat proclaims loudly shortly after walking into the audience room.
"With much grief, King Estjald will have to reconsider the alliance treaty we have with Methiant, because lately you and your courtiers seem to be actively undermining the friendship between our nations, unless you make amends and apologize to him and Cydwyllian court."
"And what of Llewyn? My son must be made heir!" Alissa shouts from her chair, and the diplomat scoffs. He then opens up a scrolls and begins to read.
"'This is the will of sovereign King Estjald of Cydwy. Hereby I proclaim that my brother Cyl, is to be made heir and successor to the throne of Cydwyl in case of my death or incapacitation. So signeth I, King Estjald, on tenth day of Midsummer of year one thousand hundred seventy one.' And this is the copy of his will, may I present it to you." The diplomat approaches your throne and hands you the paper. Signature and royal seal of Cydwyl are genuine, you can tell.
"And here is the second paper - an edict of exile for you, Lady Alissa, as well as Princess Llewyn, Tolin and Aron." He hands you the second document, and again, you can't see any mark of forgery with your skilled eye. You quickly pass the documents to the Advisor for a quick check-up.
"This is an outrage!" Yells Alissa.
"I am the true heir of Cydwyl!" Llewyn echoes after her.
"An outrage is the despicable manner in which you left the palace of your King, Lady Alissa, taking your children, only to scheme and plot behind King Estjald's back with people whom he considered his most trusted allies!" The envoy replies, only angering Alissa more.
"If he made his will clear instead of collaborating with shadowy people, if he had not ignored my polite inquiries, there would be no such situation!"
"King Estjald wished to see if your son, besides his good health, had any traits indicative of a good ruler, compared to the well-renowned and charismatic man that is Cyl. My liege told me that 'Patience is a virtue, and Lady Alissa has none'. These are words of King Estjald." Alissa's pure red face indicates that she is near boiling point, while Llewyn is gripping on his sword so hard that his knuckles are turning white. The Advisor approaches you and leans to whisper.
"The seals are genuine. Those are truly documents signed by King Estjald." Courtiers are murmuring at your court, and there are many whispering conversations. Clearly, the noblemen are split on this whole issue. This situation will require delicate manuevering, lest your courtiers get unhappy or your authority plummets.
Of course, the decisions are in your hands.
As for relationship with King Estjald of Cydwyl...
A) Write a formal letter of apology.
B) Do nothing.
C) Dissolve the alliance and declare war against the scoundrel!
D) Send him valuable gifts.
E) Renounce the alliance treaty once and for all!
As for Lady Alissa and her kids...
A) Offer to make your palace her new home.
B) Kick them out for dragging you in this terrible mess.
C) Promise to make whatever you can to ensure that she and her kids return to Cydwyl.