Mamono Hunter Youko

A girl is chosen to fight demons in order to protect humans. Also, both have a character that wants to take the job of the main girl, which is on only something they can do. 

Devil Hunter Yohko is the rated R version of Sailormoon. Same silly dialogue, with dramatic battles against cliche monsters all the while seeking to preserve the heroins love interests. Only difference is that Sailor Moon wasn't constantly trying to get laid or brutally decapitating monsters. 

Both Devil hunters and (well, in the game, Dante has to kill the King of the underworld) kills the King of the underworld for a second time.  

Same theme type, but Kocho more ecchier and funnier. 

They both are 90s series and both have a female lead that deals with supernatural things. 

Somehow watching Yohko always made me think of Chao/Katy and the Baron Ghost. Maybe it was the whole slipping her roofies and chaining her to a spire thing? Of course, Unico is a much cuter and more innocent anime. 

The animation is pretty similar. Part from that it is a action packed anime with some nudity and a good portion of comedy, the story isn't very similar. Outlanders is Sci fi and Devil Hunter Yohko is Fantasy, though they fight with swords and don't seem to use very high-tec items in Outlanders. The only thing that makes Outlanders sci fi is the space travel, pretty much.