Let's say there is new starting coin, there are few normal user's desktop running and mining that coin.
Suddenly big hash power (like 1000 or over 10000 ASIC machine) owner(big whale) comes in to mine that coin.
Thats mostly the reason why you shouldn't just copy&paste 'fork' a coin without changing parameters.
ASIC stands for
Application-
specific
integrated
circuit. They are built for 'established' coins and/or widely hashing algorithms.
1.
Then he maybe will monopoly all the blocks after, and he can mine more faster than the time developer's set like 10 seconds? Like super-fast even mine 1 block in just 0.001 second because whale has enormous hash power?
Yes, this is absolutely possible.
If its interesting for miners (regarding financial aspects) its even highly probable.
2.
If difficulty retarget period is set like 2 hours instead of 2 weeks which Bitcoin adopt, then it means after 2 hour, big whale also suffer rised difficulty maybe?
Then, what happen he left at that time?
Usually those periods aren't directly measured in hours or weeks but in the amount of blocks.
For BTC the network difficulty adjusts every 2016 blocks (which corresponds to 2 weeks with 10 minutes per block).
If the difficulty adjusts after a specific amount of blocks the network would kind of be 'screwed' in such a case.
Now difficulty is so rised, but there are none of that big whale, there is just weak few cpus exist, those maybe can't mine at all for 2 hours?
Then again, after 2 hours, difficulty retargeting again to lower to fit their weak cpu power?
If network difficulty adjusts in a time unit, then yes.
If the difficulty adjusts after X blocks, then no. In that case it would take the time it needs to get the X blocks mined until the difficulty adjusts again.