Humanity loss is insidious. At first, it may not seem that bad. You steal something, kill someone, whatever, and then make some rolls. Worse case scenario, you lose Humanity and gain a Derangement. Who cares? You have 6 more dots of Humanity, and it's only a Mild Derangement, right? Plus, how often is Depression actually going to come up? Then you kill someone else.

Here's the thing about Humanity, it gets really bad, really fast. For one thing, every time you lose some Humanity you run the risk of gaining another Derangement. The first time this happens, it's not so bad, but pick up two or three Mild Derangements, or one Severe one, and it becomes harder and harder to play your character.

Contending with a Vice is one thing, but contending with a character who cares less and less about the inhumane things they do, has to worry about their Vice, and has picked up some Derangements, is hard to manage. Characters become paranoid, or a megalomaniac, and playing with others becomes more difficult. None of that even touches on how challenging it becomes to interact with mortals.

Mortals, being rational beings for the most part, are terrified of monsters. The lower your Humanity, the more monstrous you seem. As a result, all social rolls that don't use disciplines, and not designed to intimidate are capped at your Humanity. So, no matter how much of a social bad ass your character is, if they have Humanity 5, their dice pool is set to 5. That sucks. Of course, you can still use disciplines without being affected by this, but normal interactions become difficult to say the least, and the more you rely on Disciplines, the more likely you are to break the Masquerade.

So, how do you play someone who is on a downward spiral to a horrifying monster? It's actually pretty simple, you start playing a horrifying monster. Doing this well means that you play up the aspects of your character that have gotten him into this situation, and having fun with it.

Playing Your Vice
I'll be covering Virtues and Vices in more detail at some point, but to start with, consider what it means to be prideful, or wrathful, or whatever. If your Vice is Wrath, and you have slipped down in Humanity some, then react with physical threats or violence when someone pushes you. If your Vice is Pride, and someone insults you, start planning their downfall. If your Vice is Greed, steal money from the jerk that messed with you. Hell, there are lots of ways to interpret Vices, the important thing is to make sure you react even more strongly than you normally would the lower your Humanity gets. Lose a little control, but please remember that it's still a game.

Play Your Derangement
This part is hard. I could spend several paragraphs on Derangements, but they're covered on the site already. With regards to this article, the important thing to remember is that becoming less sane is part of Humanity loss. It should make you a little unhinged, and it should make people wonder what's wrong with you.

I also highly recommend reading up on your Derangement (they are covered in the link above), and what having it means for your character. If you're a Megalomaniac, act competitive, and if you lose, act like you were cheated, and demand a rematch regardless of circumstances. If you're Paranoid, assume that any failure is because of the conspiracies of others. If you are suspicious of someone's behavior, attack or flee them immediately (if you fail the required roll). Derangements should not be fun for the character, and they should make playing them harder. Hopefully, the challenge will make for good role-playing, and hopefully that will be fun for you, the player.

Interacting With Mortals
The lower your Humanity is, the harder it is to interact with mortals. Remember this, particularly in your downtimes, and either make accommodations for it (talk to them via e-mail, im, etc.) or plan to use intimidation or Disciplines. Don't start talking to a mortal and assume everything is ok, if you have a Humanity below 5.

At lower levels of Humanity, it is sometimes easier to have a Retainer handle the mortals you have to interact with, so it can be a good idea to pick one up and start training them for that purpose. No one likes dealing with a monster, but if you're blood bound someone and/or they are loyal to you already, they might not think it's quite so bad.