Etz not da only one. Dat Isha ov da Eldar hoo know she's still alive thank her fer stuff. Ain't ever seen a priest ov Isha en battle though. Technically, da avatar ov Khaine ez a demon/warp entity.
Maybe but we all so far have forgoten to point out something really important in my opinion !That good and evil is basically a point of view !So when we talk about the deamons ability to be good from whos point of view are we discusing?!Because if we were to ask certain individuals or populations the deamons are allready good!
I imagine Good in the sense it doesn't want to be a dick to people as that is what Daemons usually do, they manipulate, possess and what not to get their way. Then again don't Daemons have a desire to be free in a sense from the being trapped in the Warp so they can explore and shit? People do crazy shit to get free so who's to say Daemons created by our emotions wouldn't do the same to try and get free.
But what about those deamons that are born by such "negative" emotions ,that are defined by those emotions and are being fed by them do they really have the choice or even the capacity to "change"? In my understanding its not freedom that they desire but new feeding grounds (afterall they need to sustain themselves somehow) and new places to shape to their "image" to serve as strongholds and/or battlegrounds for the "Game"!
I would say the best thing to ask would be Daemons or Warp Entities but then again that is just the same as asking the Riddler for a straight answer so... My guess though is I doubt they can but then again my only want from Daemons if for them to die so I might be a little biased... The Daemons that do break free of the Warp just want to explore and kind of like when the Daemon possesses Fulgrim wants to explore all the feelings that a material form has so they're hunger from experiences they haven't had before but as you've said they do require sustenance and because of it they will need to kill more and what not but Daemons usually try to impress the Chaos "Gods" like someone trying to impress their alcoholic father...
Deamons or warp entities it doesnt really matter because in the end both of these groups appear to need the materium for sustenance!But needing someone else for sustencance its not evil or good in my opinion it is just natural!It may be evil from the PoV of the man that gets nomed but from the deamons PoV its anything but that! That particular deamon was bound on a sword for a very long time(at least that is what i understood!) and being a Slaaneshi deamon it was those experiences that gave it sustenance!Along with the souls of the salin ofcourse!I dont think that comparing the Pantheon to an alcoholic is the right thing to do !In my opinion no matter the sentience and intelect that some of them posses they are more akin to a predator !
Meh, Daemons are bad. As has been stated because they feed off Human emotions and in the Imperium or Humanity in general within 40k there isn't many good emotions being given off. Usually Grimdark does that kind of thing... Needing to feed isn't necessarily bad. Just when something comes over and starts eating your battle-brothers, friends or the people you were going to eat then you're not too happy... If a Daemon was born from the hatred of Man then that is what it would be hate, could it be taught differently possibly, require a psyker powerful enough to tame it or catch it like a pokemon then with the Daemon knowing the person who'd tamed it was more powerful than them could then try to change the Daemon's psyche to not being a dick who wants to kill everything because that is how it came to be through the hatred of Man so that is all it would know. If you only knew one way to do something that's how you'd do it. If the Daemon was Humanoid it might one day question why can't I do it this way or that way but Daemons I cannot begin to try and understand their mind. Also the Chaos "Gods" usually sit doing bugger all and then only when the Chaos guys come over and say to which ever "God" here is what I've done for you then the "God" will usually do fuck all or give them a slight approval for their efforts. Daemons are bad. If another race sees it differently then fuck them. Humanity, fuck yeah!