User blog comment:Lord Loss/Monster Appreciation Day: Deviljho/@comment-76.24.129.152-20111123180300/@comment-1837917-20111124020158

It is most likely going to be a) What Artemis said, a 'Pseudo-Sub' that seems to be constantly enraged, or b) a G-Rank rage mode of some such. The only example I can think of that could be constituted as 'evolution' (which is a concept MH should avoid) is Yian Garuga, and even then it's a different species altogether.