Mulawin vs. Ravena is a Tagalog fantasy television series created and produced by GMA Network. Nowadays, a new series is often ordered (funded) for just the first 10 to 13 episodes, to gauge the audience interest.
If it is "picked up", the season is completed to the regular 20 to 26 episodes. A midseason replacement is an inexpensive short-run (10–13 episode) show designed to take the place of an original series that failed to garner an audience and has not been picked up.
Source:Wikipedia
