had a DRG in a pt once, killing colibri. Hailie was his name if I remember right.. Also had Angon.
This DRG pwned every single colibri, and Angon GREATLY reduced damage. My criticals, as slashin damage, would normally hit in the 200's, while Hailie was hitting upwards at about high 200's-300... But when he used Angon, my criticals jumped to 300ish, while his went to around the high 300's-400.
Also, Weapon Skill damage was increased by hundreds of damage points, which I dont think would be seen from just 51 defense.
But, I could be wrong. This could all be coincidence.
But anyway, DRG are very good DD if used right. I dont think a lot of people take into consideration that birds are weak to polearms/piercing
Edit: Checked Wiki, its definitely 20% decrease