A sign/abbreviation for "magister"

[James Kass via Unicode]

Responding to Julian Bradfield,

U+1D49 MODIFIER LETTER SMALL E
General Category:  Letter, Modifier
Decomposition Type <super>
Mapping:  U+0065

It's a spacing superscript Latin lower case "E".  It's a letter. People 
spell with letters.

"One of the goals of the Consortium is to preserve humanity's common 
linguistic heritage and provide universal access for the world's 
languages—past, present, and future."

Superscripts and subscripts are part of the Latin writing system. If the 
source says "yᵉ" or "þᵉ", that's what I would enter into the database.  
Otherwise it's just transcription, IMHO.  If the goal is to preserve the 
past by transcribing it, we could've done  that with ASCII.

Having "yᵉ" or "þᵉ" in the database makes the database more 
human-readable than having mark-up such as "y<sup>e</sup>" and takes 
fewer bytes.

DUCET allows for desired collation results.  Searching for "yᵉ" or "þᵉ" 
could get only those files which included the specific string and not 
all the files which include strings "ye", "þe", or "the".

The superscript lower case Latin "E" also has "grapheme base" listed as 
one of its binary properties, so it might be OK to add a line or two 
under one, if that's what's desired.

If the superscript lower case Latin letter "E", ("ᵉ"), cannot be used in 
this instance because it is supposed to *modify* the preceding 
character, then is its usage in this question a "hack"? It isn't 
modifying that ASCII quote at all.

Providing mark-up solutions isn't universal, but computer plain-text is.

For the OP's question, PUA for perfect display and no guarantee of 
interoperability, "Mr" for transcription, or (what Michael said 
initially) "Mʳ".  I think it would be OK to add something like a 
combining equals sign below to Michael's suggested string and make it 
"Mʳ͇", but it wouldn't display well unless a font's OpenType tables 
provided for it.