Is this a temporal free update? looks interesting, also the SF one is it free too?
This is a permanent addition to the game. The 5th major update. The other four are:
- Kulve Taroth
All of them are free.
The street fighter one is free as well, but that is a timed event that re-appears every now and then. It is currently available right now, as part of the Appreciation Festival, which runs for a couple of weeks.