Master Birk Familiar?

Does it actually drop from Master Birk?

No.

So the monster book is wrong?

That's because there are 2 versions of it, the one from JapanMS and the one from KoreaMS. When Nexon copy pasted the Silent Crusade from KMS, all the JMS versions got replaced with the KMS versions. However, they still drop the cards, but for the wrong monster.

Then Platoon Chronos is the best option until Mutant Snails.
Thanks!