I realise it already has a walkthrough, but that's only to end the game.
So here is how you get all the behaviors, breathes, and titles.
Titles - There are 4.
Behaviors - There are 5 (odd number, eh?).
Breathes - There are 4.
**BREATHS**
Now then, let's start with breathes, as those are the first you obtain.
Breathe None - Go to the rightmost part of the castle, you will see a well of sorts. Jump down it, and go to the far left. There will be a hole, jump through it. Then go through the hole in the floor, and go rightmost. You now have no breathe.
Breathe Fire - Eat these 4 items: The fireplace under the cage you came in, the lamp at the rightmost side of the castle (*note* not inside the well, in the tower), on the top, the candle in the baby room (2 rooms under the wizard), and the torch in the well (you can jump back up).
Breathe Heal - Eat the blue mushrooms in the sewer (entered through the well), the health vile next to the candle, a sack of... blue stuff in the rightmost tower (mid floor), and the health vile directly under the wizard's room.
Breathe Plant - The plant thing directly above the cage room, bottom leftmost corner of the castle, there is a small plant, in the rightwards passageway there is a tree, and the room above the dining hall yields another plant. Eat those and you're set.
**BEHAVIORS**
Fiery - Needs Fire Breathe - Torch EVERYTHING, and sit on either the building for a tyrant, or sit on the rightmost area for a scourge.
Necromantic - Needs Heal Breathe - resurrect things! Either by squashing humans and healing them, or ... well that's just about it. Sit on the building for tyrant or the rightmost area for scourge.
Rampaging - Can Be Used By Any - Eat everything in your path. EVERYTHING. Then sit on the building in order to get tyrant, or in the rightmost area scourge.
Reclusive - Can Be Used By Any - Simply not kill anything. Sit on the building to be a guardian and sit on the rightmost area to be a watcher. **note, I think this is the only way to get the watcher**
Wild - Needs Plant Breathe - Plant EVERYTHING. and do it with fuuuun! XD. Or at least most, but I plant breathed everything for good measure. Then sit on the building for a guardian, or the rightmost area for a watcher/scourge.
**TITLES**
Guardian - Can Be Used By Any - Simply not kill anything and sit on the building.
Tyrant - beat the crap out of everyone and then sit on the building.
Watcher - I think that you can only do this with reclusive nature but I'm not sure. So then, just not kill and go to the rightmost area.
Scourge - Kill all you want, burninate all you want, just go to the rightmost corner.