I love Devil You Know!! I gotta ask though how do you do the different font and colors. Like I've looked at html guides and I just don't get them :( Any advice or what your html text looks like please?
hi, thank you so much! i can totally answer this, because it took me forever to figure this out on my own.
so this is what my “chat” dialogue looks like in devil you know:

i’m actually not using html (technically); i’m using ao3′s built-in skin feature! this basically lets you set custom CSS tags that you can then use throughout your fic, if you apply the skin.
there are presets you can use– think old homestuck fics– but you can also make your own. that’s what i did. i’ll try to explain how i did it, and if you have any further questions, let me know! there are probably other good resources out there, and ao3 has a “wizard” feature, too.
so you go to your ao3 dashboard, then “skins,” and choose to create a new work skin. you’re gonna use CSS. here’s what mine looks like:

keep #workskin. the “.rhys” value is how you’re going to “refer” to this formatting command in your actual work; i’ll show you what that looks like in a minute. so replace “rhys” there with any keyword you want. after that, you’re just listing the CSS you want to use.
when you’re publishing your fic, make sure you apply this skin.
then, in the HTML for your fic, you’re going to use this HTML around the text you want to change:

so basically, that’s going to be:

“YOURKEYWORD” is whatever you put after the period in your workskin.
Sorry, I probably explained that very very badly… there are good tutorials out there, I’m sure. if you have any more questions about it i will gladly try to elaborate! but this is about the extent of my knowledge :’)