I'm soon to be taking the step into my first time as a DM for a group I have played with for some time as a player. I have a few ideas for the adventure I'm going to run, but I find myself stumbling when it comes to creating the final boss in an undead-centric homebrew 5e campaign. The boss I have in mind would be Doresain, King of Ghouls, but the only thing I have been able to find is a 4e version with the old stats system.
What would be the best way to go about bringing this boss forward from the older edition? Finding a way to mix and match existing abilities of other boss-tiered enemies to try and recreate the old enemy? Or, instead, to create a homebrew version on my own from scratch and attempt to playtest it solo until it's beatable? Do you have any recommendations for the stats/ abilities that could make a good 5e version of this character either way?