What book / page has the info for drake characters?

In 3rd Edition, Threats 2 has the info.

Really? And they didn't dump it into any of the SOTA's or anything?
Great. I'm pretty sure I know where my Threats 2 book is

DotSW has infos about Drakes too iirc.

I haven't read about them in a long time, but wasn't the information in both Dragons of the Sixth World and Threats 2?

Threats 2: introduction to drakes
DotSW: more stats and rules for the weaker bred drakes which have rules for chargen pricing so they can be played without an excessive amount of GM fiat.

what are the rules for playing a drake?

Sorry if my comments were misleading: I don't have Dragons of the Sixth World yet, so I couldn't speak to the info contained in that book.

Straight Razor: take a look at those books, the rules are too long (not to mention too copy-written) to post here. Drakes can be extremely fun characters in the right context.

Simple form: you pay a lot of BP, you get a secondary physical form, you don't regenerate, but you also don't have to pay double for your attributes, you also get innate spell(flamethrower) in drake form.

Yes, there's more to it, but that should be enough to help you decide if you want to learn the rest.