Shallam, you lucky ducks, you have Brendan as a vizier.
Sure, his commonsense is lacking to a extreme degree, but his sleuth
skills more than make up for it! Well done Brendan on discovering
the mastermind behind who sent this letter. You are a true asset to
your city. Just a few points...

Why would RL incriminate themselves on matters like these?
Isn't the poor grammar and spelling unusual for RL documents?
Dropping letters in cities is a practise more common with those of
Bloodlochs militia. RL is a particularly officious organisation,
perishable documents such as letters are rarely acceptable.
Why would this person who seemingly doesn't care go to such great
lengths to hide their identity?
Why would RL reveal information like that?
Why would RL write a letter with undertones of animosity towards
themselves?

Read between the lines Brendan, you are likely to find that your
mystery writer is not so hard to track down. In fact, I would
strongly encourage the divine to find out who wrote it, and will
offer any ideas I have on finding the person to anyone interested.

Torkah Ru'Ach

Penned by my hand on the 16th of Chakros, in the year 124 MA.