Well so far I'm open minded about species.  

Meaning you can be any of the introduced ones in Mlp really. 

Or a bit of a custom one.  The only main rule about it is that they should be fairly equal or smaller than a pony. 

Like griffin etc,  if you want a reindeer or whatever that can also be fixed. 

I may,  just maybe accept. Single new Alicorn,  but it have to fill a rather specific role xD.