Talk:Debuff/@comment-3974211-20120325124135

There is a fourth source.

The Dragon in Summoner's Rift reduces attack speed. Baron Nashor's applies a stacking debuff that increases magic damage you take. His applies a non-stacking debuf that reduces your AD.



P.S. There is an easier way to know if something is a debuff or not. If it isn't a buff, but it appears in the buff-bar and can be removed by then it is a debuff. RE below: is in the buff bar and can be removed by QSS, thus, it's a debuff. :)