Depression: (
Story/Location) Titles that contain characters who suffer from depression would fall into this category if this is of significant importance for the storyline.
Violent: (
Objectionable Content)
Titles that include as an important part of their content excessive displays of cruelty, blood and gore. Any of the classical 'slasher' films would qualify for this keyword. The series
Black Lagoon would be a good example; as many of its chapters involve killer lolis, chainsaw mercenaries and flying body parts.
Parody: (
Genre) This would be a title which closely imitates another title, genre, culture, etc. for comic effect or in ridicule.
Modern: (
Setting) These are titles which have a modern feel to them; the story takes place in the present day (of the creation of this anime), give or take a few years.