Defender's Crest - What's it do?

[Kyutaru]

Found a charm that gives me an odor. What's that good for? <_<

[DeamonHal]

As far as I know it deals a very small amount of damage to enemies in the odor cloud.

[Mister Veeg]

Several NPCs reference your terrible stench

apparently fragile charm guy gives you a discount for it ('least, from the sound of his "listen" prompt, I already had all his charms by then so idk if it's legit).

[Colonel Mustache]

A cloud of odor follows you around, persisting slightly if you move from your spot. I find it surprisingly helpful - I used it throughout most of the game. If you combine it with the mushroom spore charm, it turns that cloud the same color as your odor, which is a nice touch.