Dark knight

fancy that.
What a surprise!

fiend---a very cruel, evil, or violent person

sb's (main) squeeze
especially AmE informal someone's boyfriend or girlfriend

rack them up

1. Lit. to place something onto or into its rack.

2. Fig. to accumulate something; to collect or acquire something.

3. Sl. to wreck or damage something.

play it (the cards) close to the vest(chest),
to not tell anyone what you plan to do

now, we're talking.　
joker說的話。
前幾天讀jigsaw jones第二集時，在找銅板時跟工友談話時，工友也說了這句話。
意思是這可有意思了。