- A warm and nice guy (Do Hyun in Kill me Heal me!!)

- A cold/heartless guy (a soldier? a secret agent? a crown prince? someone who has to keep a cool head and follow logic instead of emotions or something) that possibly STAYS, at least in part, like that and doesn't become completely weak

- a nice guy who becomes a cold/ruthless guy (notice: not your typical bad boy who was nice when he was 15 in the three flash backs that they show during the whole drama) 

- your typical spoiled and petty guy who looks like his life is all sunshine and rainbows but it actually isn't or something (Joo Won in Secret Garden !!)

It'd be really helpful if you could indicate in which category the male lead of the suggested dramas falls in :)

- A warm and nice guy (Do Hyun in Kill me Heal me!!)

Shopping king Louis
Weightlifting fairy
Soratobu Kouhoushitsu
Flower boy next door
That Fool
Can you hear my heart
Mary Stayed Out All Night
Nigeru wa Haji da ga Yaku ni Tatsu
Nagareboshi
Queen In Hyun's Man

- A cold/heartless guy (a soldier? a secret agent? a crown prince? someone who has to keep a cool head and follow logic instead of emotions or something) that possibly STAYS, at least in part, like that and doesn't become completely weak

Any version of: it started with a kiss
Good morning call 
Pride (jdrama)
Hotaru no Hikari
Moon Lovers: Scarlet Heart Ryeo
Nodame Cantabile

- a nice guy who becomes a cold/ruthless guy (notice: not your typical bad boy who was nice when he was 15 in the three flash backs that they show during the whole drama) 

Innocent guy
The princess' man

- your typical spoiled and petty guy who looks like his life is all sunshine and rainbows but it actually isn't or something (Joo Won in Secret Garden !!)

Hana yori Dango
It's Okay, That's Love
Mask