I have always felt that fiends are significantly stronger than other monster types, and today, I figured out why: they have the singular ability to change the direction of the attack after it has been 'announced' (the coloured indicator), but before it has been executed - beasts, undead, constructs, and slimes do not do this, and gremlins only do it rarely, and to a lesser extent (note, gremlins are my second-least favourite class, though this is more because of deconstruction zones, when there are clumps of 10, all carrying shields).
The three main types of fiend (devilite, gorgo and greaver) all do this (and trojans more often appear in conjunction with undeads).
Comments?
Edit: all classes of gun turrets do this to an extent as well (thought not as much as fiends), but they have the downside of being stationary
A lot of enemies used to be harder in the past. OOO has nerfed plenty of them, such as Wolvers and Zombies. However, there are still plenty of enemies which can change direction after telegraphing. Kats, Mecha Knights, and so on. Personally, I like this. I wish that all enemies which have been nerfed would have their nerfs reverted in Elite difficulty, to spice the game up a bit. Thoughts on the fiends you listed: